presentation of vertex

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Fetal Presentation, Position, and Lie (Including Breech Presentation)

, MD, Children's Hospital of Philadelphia

Variations in Fetal Position and Presentation

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Presentation refers to the part of the fetus’s body that leads the way out through the birth canal (called the presenting part). Usually, the head leads the way, but sometimes the buttocks (breech presentation), shoulder, or face leads the way.

Position refers to whether the fetus is facing backward (occiput anterior) or forward (occiput posterior). The occiput is a bone at the back of the baby's head. Therefore, facing backward is called occiput anterior (facing the mother’s back and facing down when the mother lies on her back). Facing forward is called occiput posterior (facing toward the mother's pubic bone and facing up when the mother lies on her back).

Lie refers to the angle of the fetus in relation to the mother and the uterus. Up-and-down (with the baby's spine parallel to mother's spine, called longitudinal) is normal, but sometimes the lie is sideways (transverse) or at an angle (oblique).

For these aspects of fetal positioning, the combination that is the most common, safest, and easiest for the mother to deliver is the following:

Head first (called vertex or cephalic presentation)

Facing backward (occiput anterior position)

Spine parallel to mother's spine (longitudinal lie)

Neck bent forward with chin tucked

Arms folded across the chest

If the fetus is in a different position, lie, or presentation, labor may be more difficult, and a normal vaginal delivery may not be possible.

Variations in fetal presentation, position, or lie may occur when

The fetus is too large for the mother's pelvis (fetopelvic disproportion).

The fetus has a birth defect Overview of Birth Defects Birth defects, also called congenital anomalies, are physical abnormalities that occur before a baby is born. They are usually obvious within the first year of life. The cause of many birth... read more .

There is more than one fetus (multiple gestation).

Position and Presentation of the Fetus

Some variations in position and presentation that make delivery difficult occur frequently.

Occiput posterior position

In occiput posterior position (sometimes called sunny-side up), the fetus is head first (vertex presentation) but is facing forward (toward the mother's pubic bone—that is, facing up when the mother lies on her back). This is a very common position that is not abnormal, but it makes delivery more difficult than when the fetus is in the occiput anterior position (facing toward the mother's spine—that is facing down when the mother lies on her back).

Breech presentation

In breech presentation, the baby's buttocks or sometimes the feet are positioned to deliver first (before the head).

When delivered vaginally, babies that present buttocks first are more at risk of injury or even death than those that present head first.

The reason for the risks to babies in breech presentation is that the baby's hips and buttocks are not as wide as the head. Therefore, when the hips and buttocks pass through the cervix first, the passageway may not be wide enough for the head to pass through. In addition, when the head follows the buttocks, the neck may be bent slightly backwards. The neck being bent backward increases the width required for delivery as compared to when the head is angled forward with the chin tucked, which is the position that is easiest for delivery. Thus, the baby’s body may be delivered and then the head may get caught and not be able to pass through the birth canal. When the baby’s head is caught, this puts pressure on the umbilical cord in the birth canal, so that very little oxygen can reach the baby. Brain damage due to lack of oxygen is more common among breech babies than among those presenting head first.

Breech presentation is more likely to occur in the following circumstances:

Labor starts too soon (preterm labor).

Sometimes the doctor can turn the fetus to be head first before labor begins by doing a procedure that involves pressing on the pregnant woman’s abdomen and trying to turn the baby around. Trying to turn the baby is called an external cephalic version and is usually done at 37 or 38 weeks of pregnancy. Sometimes women are given a medication (such as terbutaline ) during the procedure to prevent contractions.

Other presentations

In face presentation, the baby's neck arches back so that the face presents first rather than the top of the head.

In brow presentation, the neck is moderately arched so that the brow presents first.

Usually, fetuses do not stay in a face or brow presentation. These presentations often change to a vertex (top of the head) presentation before or during labor. If they do not, a cesarean delivery is usually recommended.

In transverse lie, the fetus lies horizontally across the birth canal and presents shoulder first. A cesarean delivery is done, unless the fetus is the second in a set of twins. In such a case, the fetus may be turned to be delivered through the vagina.

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Vertex Position: What It Is, Why It's Important, and How to Get There

Jamie Grill / Getty Images

What Is the Vertex Position?

• Why It's Important

When the Vertex Position Usually Occurs

• How to Get Baby in This Position

Options if Baby Is Not in the Vertex Position

While you are pregnant, you may hear your healthcare provider frequently refer to the position or presentation of your baby, particularly as you get closer to your due date . What they are referring to is which part of your baby is presenting first—or which part is at the lower end of your womb or the pelvic inlet.

Consequently, when they tell you that your baby's head is down, that likely means they are in the vertex position (or another cephalic position). This type of presentation is the most common presentation in the third trimester. Here is what you need to know about the vertex position including how you might get your baby into that position before you go into labor .

The vertex position is a medical term that means the fetus has its head down in the maternal pelvis and the occipital (back) portion of the fetal skull is in the lowest position or presenting, explains Jill Purdie, MD, an OB/GYN and medical director at Northside Women’s Specialists , which is part of Pediatrix Medical Group.

When a baby is in the vertex position, their head is in the down position in the pelvis in preparation for a vaginal birth, adds Shaghayegh DeNoble, MD, FACOG , a board-certified gynecologist and a fellowship-trained minimally invasive gynecologic surgeon. "More specifically, the fetus’s chin is tucked to the chest so that the back of the head is presenting first."

Why the Vertex Position Is Important

When it comes to labor and delivery, the vertex position is the ideal position for a vaginal delivery, especially if the baby is in the occiput anterior position—where the back of the baby's head is toward the front of the pregnant person's pelvis, says Dr. DeNoble.

"[This] is the best position for vaginal birth because it is associated with fewer Cesarean sections , faster births, and less painful births," she says. "In this position, the fetus’s skull fits the birth canal best. In the occiput posterior position, the back of the fetus's head is toward the [pregnant person's] spine. This position is usually associated with longer labor and sometimes more painful birth."

Other fetal positions are sometimes less-than-ideal for labor and delivery. According to Dr. DeNoble, they can cause more prolonged labor, fetal distress, and interventions such as vacuum or forceps delivery and Cesarean delivery.

"Another important fact is that positions other than vertex present an increased risk of cord prolapse, which is when the umbilical cord falls into the vaginal canal ahead of the baby," she says. "For example, if the fetus is in the transverse position and the [pregnant person's] water breaks , there is an increased risk of the umbilical cord prolapsing through the cervix into the vaginal canal."

When it comes to your baby's positioning, obstetricians will look to see what part of the fetus is in position to present during vaginal birth. If your baby’s head is down during labor, they will look to see if the back of the head is facing your front or your back as well as whether the back of the head is presenting or rather face or brow, Dr. DeNoble explains.

"These determinations are important during labor, especially if there is consideration to the use of a vacuum or forceps," she says.

According to Dr. Purdie, healthcare providers will begin assessing the position of the baby as early as 32 to 34 weeks of pregnancy. About 75% to 80% of fetuses will be in the vertex presentation by 30 weeks and 96% to 97% by 37 weeks. Approximately 3% to 4% of fetuses will be in a non-cephalic position at term, she adds.

Typically, your provider will perform what is called Leopold maneuvers to determine the position of the baby. "Leopold maneuvers involve the doctor placing their hands on the gravid abdomen in several locations to find the fetal head and buttocks," Dr. Purdie explains.

If your baby is not in the vertex position, the next most common position would be breech, she says. This means that your baby's legs or buttocks are presenting first and the head is up toward the rib cage.

"The fetus may also be transverse," Dr. Purdie says. "The transverse position means the fetus is sideways within the uterus and no part is presenting in the maternal pelvis. In other words, the head is either on the left or right side of the uterus and the fetus goes straight across to the opposite side."

There is even a chance that your baby will be in an oblique position. This means they are at a diagonal within the uterus, Dr. Purdie says. "In this position, either the head or the buttocks can be down, but they are not in the maternal pelvis and instead off to the left or right side."

If your baby's head is not down, your provider will look to see if the buttocks are in the pelvis or one or two feet, Dr. DeNoble adds. "If the baby is laying horizontally, then the doctor needs to know if the back of the baby is facing downwards or upwards since at a Cesarean delivery it can be more difficult to deliver the baby when the back is down."

How to Get Baby Into the Vertex Position

One way you can help ensure that your baby gets into the vertex position is by staying active and walking, Dr. Purdie says. "Since the head is the heaviest part of the fetus, gravity may help move the head around to the lowest position."

If you already know that your baby is in a non-cephalic position and you are getting close to your delivery date, you also can try some techniques to encourage the baby to turn. For instance, Dr. Purdie suggests getting in the knee/chest position for 10 minutes per day. This has been shown to turn the baby around 60% to 70% of the time.

"In this technique, the mother gets on all fours, places her head down on her hands, and leaves her buttock higher than her head," she explains. "Again, we are trying to allow gravity to help us turn the fetus."

You also might consider visiting a chiropractor to try and help turn the fetus. "Most chiropractors will use the Webster technique to encourage the fetus into a cephalic presentation," Dr. Purdie adds.

There also are some home remedies, including using music, heat, ice, and incense to encourage the fetus to turn, she says. "These techniques do not have a lot of scientific data to support them, but they also are not harmful so can be tried without concern."

You also can try the pelvic tilt , where you lay on your back with your legs bent and your feet on the ground, suggests Dr. DeNoble. Then, you tilt your pelvis up into a bridge position and stay in this position for 10 minutes. She suggests doing this several times a day, ideally when your baby is most active.

"Another technique that has helped some women is to place headphones low down on the abdomen near the pubic bone to encourage the baby to turn toward the sound," Dr. DeNoble adds. "A cold bag of vegetables can be placed at the top of the uterus near the baby’s head and something warm over the lower part of the uterus to encourage the baby to turn toward the warmth. [And] acupuncture has also been used to help turn a baby into a vertex position."

If you are at term and your baby is not in the vertex position (or some type of cephalic presentation), you may want to discuss the option of an external cephalic version (ECV), suggests Dr. Purdie. This is a procedure done in the hospital where your healthcare provider will attempt to manually rotate your baby into the cephalic presentation.

"There are some risks associated with this and not every pregnant person is a candidate, so the details should be discussed with your physician," she says. "If despite interventions, the fetus remains in a non-cephalic position, most physicians will recommend a C-section for delivery."

Keep in mind that there are increased risks for your baby associated with a vaginal breech delivery. Current guidelines by the American College of Obstetricians and Gynecologists recommend a C-section in this situation, Dr. Purdie says.

"Once a pregnant person is in labor, it would be too late for the baby to get in cephalic presentation," she adds.

A Word From Verywell

If your baby is not yet in the vertex position, try not to worry too much. The majority of babies move into either the vertex position or another cephalic presentation before they are born. Until then, focus on staying active, getting plenty of rest, and taking care of yourself.

If you are concerned, talk to your provider about different options for getting your baby to move into the vertex position. They can let you know which tips and techniques might be right for your situation.

American College of Obstetrics and Gynecology. Obstetrics data definitions .

National Library of Medicine. Vaginal delivery .

Sayed Ahmed WA, Hamdy MA. Optimal management of umbilical cord prolapse .  Int J Womens Health . 2018;10:459-465. Published 2018 Aug 21. doi:10.2147/IJWH.S130879

Hjartardóttir H, Lund SH, Benediktsdóttir S, Geirsson RT, Eggebø TM. When does fetal head rotation occur in spontaneous labor at term: results of an ultrasound-based longitudinal study in nulliparous women .  Am J Obstet Gynecol . 2021;224(5):514.e1-514.e9. doi:10.1016/j.ajog.2020.10.054

Management of breech presentation: green-top guideline no. 20b .  BJOG: Int J Obstet Gy . 2017;124(7):e151-e177. doi:10.1111/1471-0528.14465

Kenfack B, Ateudjieu J, Ymele FF, Tebeu PM, Dohbit JS, Mbu RE. Does the advice to assume the knee-chest position at the 36th to 37th weeks of gestation reduce the incidence of breech presentation at delivery?   Clinics in Mother and Child Health . 2012;9:1-5. doi:10.4303/cmch/C120601

Cohain JS. Turning breech babies after 34 weeks: the if, how, & when of turning breech babies .  Midwifery Today Int Midwife . 2007;(83):18-65.

American College of Obstetrics and Gynecology. If your baby is breech .

By Sherri Gordon Sherri Gordon, CLC is a published author, certified professional life coach, and bullying prevention expert. 

Vertex Presentation: How does it affect your labor & delivery?

Medically Reviewed by: Dr. Veena Shinde (M.D, D.G.O,  PG – Assisted Reproductive Technology (ART) from Warick, UK) Mumbai, India

• >> Post Created: February 11, 2022
• >> Last Updated: April 10, 2024

Vertex Position - Table of Contents

As you approach the due date for your baby’s delivery, the excitement and apprehensions are at their peak! What probably adds to the anxieties are the medical terms describing the baby, its ‘position’ and ‘presentation.’ Let’s strike that out from the list now!

In simple words, ‘ position ’ of the baby is always in reference to the mother ; on what side of the mother’s pelvis does the baby lean more (left or right) and if the baby is facing the mother’s spine or belly (anterior or posterior) – for eg.: Left Occiput Anterior , Right Occiput Anterior , Right Occiput Posterior and so on.

On the other hand, ‘ presentation’ is the body part of baby (head, shoulder, feet, and buttocks) that will enter the mother’s pelvic region first at the beginning of labor.

As ‘ presentation’ depends on the ‘ position’ of the baby, the terms cannot be used interchangeably, which is often mistakenly done. If you are told by your doctor that your baby is in a head-down position , which means its head will enter the pelvic region first , then it means the baby is in ‘vertex’ presentation or even sometimes loosely referred to as vertex position of baby though its conceptually incorrect however it means the same.

With this article, we aim to explain how exactly vertex presentation affects your labor and delivery.

Understanding Vertex Presentation

If your baby is in the head-down position by the third trimester, then you are one of the 95% mothers who have a vertex baby or a vertex delivery. When the baby enters the birth canal head first, then the top part of the head is called the ‘vertex.’

In exact medical terms, we give you the definition of vertex presentation by the American College of Obstetrics and Gynecologists (ACOG) – “a fetal presentation where the head is presenting first in the pelvic inlet.”

Besides vertex presentation (also sometimes referred to as vertex position of baby or vertex fetal position also), the other occasional presentations (non-vertex presentations) include –

• Breech – baby’s feet or buttocks are down and first to enter the mother’s pelvic region. Head is near the mother’s ribs
• Transverse – baby’s shoulder, arm or even the trunk are the first to enter the pelvis, as the baby is laying on the side and not in a vertical position 

It is common that babies turn to a particular position (hence, affecting the presentation) by 34 -36 weeks of pregnancy. Nevertheless, some babies have ‘unstable lies’ ; – wherein the baby keeps changing positions towards the end of the pregnancy and not remaining in any one position for long.

Should you be worried if the baby is in vertex presentation?

Absolutely not! The vertex presentation is not only the most common, but also the best for a smooth delivery. In fact, the chances of a vaginal delivery are better if you have a vertex fetal position.

By 36 weeks into pregnancy, about 95% of the babies position themselves to have the vertex presentation. However, if your baby hasn’t come into the vertex fetal position by this time, then you can talk to your doctor about the options.

You may be suggested a cephalic version procedure   also known as the version procedure /external cephalic version (ECV procedure) – which is used to turn the baby/ fetus from a malpresentation – like breech, oblique or transverse (which occur just about 3-4% times) to the cephalic position (head down).

This is how your doctor will try to turn your baby manually by pushing on your belly to get the baby into the vertex presentation. But it is necessary for you to know that this procedure does involve some risk and is successful only 60-70% of the time.

Continue reading below ↓

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Risks of vertex position of baby: can there be any complications for the baby in the vertex presentation.

As discussed above, the vertex fetal position/presentation is the best for labor and delivery, but there can be some complications as the baby makes its way through the birth canal. One such complication can arise if the baby is on the larger side. The baby can face difficulty while passing through the birth canal even if it is in the head-down position because of the size.

Babies who weigh over 9 to 10 pounds are called ‘ macrosomic’ or even referred to as fetal macrosomia , and they are at a higher risk of getting their shoulders stuck in the birth canal during delivery, despite being in the head-down position.

In such cases, to avoid birth trauma for the baby, the American College of Obstetricians and Gynecologists (ACOG) suggests that cesarean deliveries should be limited to estimated fetal weights of at least 11 pounds in women without diabetes and about 9 pounds in women with diabetes.

In case of fetal macrosomia, your doctor will monitor your pregnancy more often and work out a particular birth plan for you subject to your age (mothers age) and size of your baby.

How will I deliver a baby in the vertex fetal position?

Even unborn human babies can astonish you if you observe the way they make their way through the birth canal during delivery.

A vertex baby may be in the optimal position ( head-down first in pelvis) for labor and delivery, but it does its own twisting and turning while passing through the birth canal to fit through. In humans, unlike other mammals, the ratio of the baby’s head to the space in the birth canal is quite limited.

The baby has to flex and turn its head in different positions to fit through and ultimately arrive in this world. And it does so successfully! It is a wonder how they know how to do this so naturally.

And to answer the question ‘how will I deliver a baby in the vertex position?’ – Simply NATURALLY i.e. vaginal delivery. Don’t worry, follow your doctor’s instructions, do your breathing and PUSH.

FAQs to keep ready: How can my doctor help me prepare as I approach my due date?

As your due date nears, apart from bodily discomfort, you may experience nervousness about the big day. Your doctor can help by clearing your doubts and putting you at ease. You can ask them the following questions to understand the process better.

Q1) How will I know if my baby is in vertex fetal position?

A doctor can confidently tell you whether or not your baby is in the vertex presentation. Many medical professionals will be able to determine your baby’s position merely by using their hands; this is called ‘Leopold’s maneuvers.’

However, in case they aren’t very confident about the baby’s position even after this, then an ultrasound can confirm the exact position of the baby.

You can also understand this through belly mapping . You are sure to feel the kicks towards the top of your stomach and head (distinct hard circular feel) towards your pelvis. 

Q2)Is there any risk of my vertex baby turning and changing positions?

Yes, in case of some women, the baby who has a vertex presentation may turn at the last moment.

What may cause this? Women who have extra amniotic fluid (polyhydramnios) have increased chances of a vertex baby turning into a breech baby at the last minute.

Discuss this with your doctor to understand what are the chances this might happen to you and what all you can do to keep the baby in the vertex presentation for delivery.

Q3) Is there need to be worried if my baby has a breech presentation?

Not really! There are loads of exercises which you which can help you get your baby in the right position.

Then there are the ECV (external cephalic version) procedure which can help in changing the position of your baby into the desired vertex position. Speak with your doctor.

Having a baby in breech position just before labor will require you to have a C-section . Let your doctor guide you. But there is nothing to worry about.

Q4) What may cause babies to come into breech position?

A few circumstances may cause the baby to come into breech position even after 36 weeks into pregnancy.

• If you are carrying twins or multiple babies , in which case there is limited space for each baby to move around.
• Low levels of amniotic fluid which restricts the free movement of the baby or even high levels of amniotic fluid that does not permit the baby to remain in any one position.
• If there are abnormalities in the uterus or other conditions like low-lying placenta or large fibroids in the lower part of the uterus.

Chances of breech babies are higher in births that are pre-term as the baby does not get enough time to flip into a head-down position – cephalic position – vertex presentation (vertex position of baby/ vertex fetal position).

Q5) Can a baby turn from breech position to vertex presentation?

Yes, a baby can turn from a breech position to vertex position / vertex fetal position over time with exercises and sometimes through ECV.

If an ultrasound has confirmed you have a breech baby, then you can do the following to turn it to a vertex baby. Try the following –

• Do not underestimate the wonders of daily walks of about 45-60 mins when it comes to bringing your baby in vertex presentation from breech presentation.
• Talk to your doctor about certain exercises that can help turn your baby in the head-down position. Exercises like ‘ high bridge’ or ‘cat and camel’ can help here. We recommend you to learn and try this only in the presence of a professional.
• External Cephalic Version (ECV ) is a way to manually maneuver the baby to vertex presentation. It is done with the help of an ultrasound and generally after 36 weeks into pregnancy. However, it has the success rate of just 50%. Discuss the risks, if any, with your gynecologist before opting for this procedure.

There are a couple of other unscientific methods that may not be safe to try –

• Light : Placing a torch near your vagina may guide the baby toward the light, and hence, get it in the vertex presentation.
• Music : Playing music near your belly’s bottom may urge the baby to move itself in the head-down position.

Q6) What all can I do to ensure I have a healthy delivery?

A healthy delivery requires the mother to be active, eating well, and staying happy. For any apprehensions regarding labor and delivery, do not hesitate to talk to your doctor and clarify your doubts.

Your doctor can help you understand your baby’s position and presentation, and then based on that they can plan your delivery to ensure your baby’s birth will happen in the safest possible way.

Try and maintain a healthy lifestyle which will also help in overall of your child and placenta health .

Key Takeaway

Yes, vertex presentation or vertex position of baby and vertex delivery are very common, normal, safe, and the best for labor and delivery of the baby. There is probability of complications sometimes, but that is only subject to certain conditions that we discussed above.

However, understand that any other baby position is also safe. The only thing with other positions and presentations is that the chances of a cesarean delivery goes up. Nevertheless, know what matters at the end of it all is a happy and healthy baby in your arms!

Happy pregnancy!

Khushboo Kirale

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• Third Trimester
• Labor & Delivery

What Is Vertex Presentation?

Vertex presentation is just medical speak for “baby’s head-down in the birth canal and rearing to go!” About 97 percent of all deliveries are headfirst, or vertex—and rare is the OB who will try to deliver any other way.

Other, less common presentations include breech (when baby’s head is near your ribs) and transverse (which means the shoulder, arm or trunk is due to come out first because baby is lying on his side). Most babies will turn by about 34 weeks, but some have “unstable lies,” meaning they’re like a politician trying to make everyone happy—that is, they frequently flip positions.

About 95 percent of all babies will be head-down and ready to go by delivery day. If your little one isn’t vertex by 36 weeks, ask your doctor about your options. She may recommend doing a version procedure , in which the doctor tries to manually turn baby by pushing on your abdomen, but it does carry some risks and is only about 60 to 70 percent successful.

Expert: Melissa M. Goist, MD, assistant professor, obstetrics and gynecology, The Ohio State University Medical Center.

Please note: The Bump and the materials and information it contains are not intended to, and do not constitute, medical or other health advice or diagnosis and should not be used as such. You should always consult with a qualified physician or health professional about your specific circumstances.

Plus, more from The Bump:

Delivering a breech baby?

Shift breech baby before birth?

Will my baby be breech?

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• Fetal presentation before birth

The way a baby is positioned in the uterus just before birth can have a big effect on labor and delivery. This positioning is called fetal presentation.

Babies twist, stretch and tumble quite a bit during pregnancy. Before labor starts, however, they usually come to rest in a way that allows them to be delivered through the birth canal headfirst. This position is called cephalic presentation. But there are other ways a baby may settle just before labor begins.

Following are some of the possible ways a baby may be positioned at the end of pregnancy.

Head down, face down

When a baby is head down, face down, the medical term for it is the cephalic occiput anterior position. This the most common position for a baby to be born in. With the face down and turned slightly to the side, the smallest part of the baby's head leads the way through the birth canal. It is the easiest way for a baby to be born.

Head down, face up

When a baby is head down, face up, the medical term for it is the cephalic occiput posterior position. In this position, it might be harder for a baby's head to go under the pubic bone during delivery. That can make labor take longer.

Most babies who begin labor in this position eventually turn to be face down. If that doesn't happen, and the second stage of labor is taking a long time, a member of the health care team may reach through the vagina to help the baby turn. This is called manual rotation.

In some cases, a baby can be born in the head-down, face-up position. Use of forceps or a vacuum device to help with delivery is more common when a baby is in this position than in the head-down, face-down position. In some cases, a C-section delivery may be needed.

Frank breech

When a baby's feet or buttocks are in place to come out first during birth, it's called a breech presentation. This happens in about 3% to 4% of babies close to the time of birth. The baby shown below is in a frank breech presentation. That's when the knees aren't bent, and the feet are close to the baby's head. This is the most common type of breech presentation.

If you are more than 36 weeks into your pregnancy and your baby is in a frank breech presentation, your health care professional may try to move the baby into a head-down position. This is done using a procedure called external cephalic version. It involves one or two members of the health care team putting pressure on your belly with their hands to get the baby to roll into a head-down position.

If the procedure isn't successful, or if the baby moves back into a breech position, talk with a member of your health care team about the choices you have for delivery. Most babies in a frank breech position are born by planned C-section.

Complete and incomplete breech

A complete breech presentation, as shown below, is when the baby has both knees bent and both legs pulled close to the body. In an incomplete breech, one or both of the legs are not pulled close to the body, and one or both of the feet or knees are below the baby's buttocks. If a baby is in either of these positions, you might feel kicking in the lower part of your belly.

If you are more than 36 weeks into your pregnancy and your baby is in a complete or incomplete breech presentation, your health care professional may try to move the baby into a head-down position. This is done using a procedure called external cephalic version. It involves one or two members of the health care team putting pressure on your belly with their hands to get the baby to roll into a head-down position.

If the procedure isn't successful, or if the baby moves back into a breech position, talk with a member of your health care team about the choices you have for delivery. Many babies in a complete or incomplete breech position are born by planned C-section.

When a baby is sideways — lying horizontal across the uterus, rather than vertical — it's called a transverse lie. In this position, the baby's back might be:

• Down, with the back facing the birth canal.
• Sideways, with one shoulder pointing toward the birth canal.
• Up, with the hands and feet facing the birth canal.

Although many babies are sideways early in pregnancy, few stay this way when labor begins.

If your baby is in a transverse lie during week 37 of your pregnancy, your health care professional may try to move the baby into a head-down position. This is done using a procedure called external cephalic version. External cephalic version involves one or two members of your health care team putting pressure on your belly with their hands to get the baby to roll into a head-down position.

If the procedure isn't successful, or if the baby moves back into a transverse lie, talk with a member of your health care team about the choices you have for delivery. Many babies who are in a transverse lie are born by C-section.

If you're pregnant with twins and only the twin that's lower in the uterus is head down, as shown below, your health care provider may first deliver that baby vaginally.

Then, in some cases, your health care team may suggest delivering the second twin in the breech position. Or they may try to move the second twin into a head-down position. This is done using a procedure called external cephalic version. External cephalic version involves one or two members of the health care team putting pressure on your belly with their hands to get the baby to roll into a head-down position.

Your health care team may suggest delivery by C-section for the second twin if:

• An attempt to deliver the baby in the breech position is not successful.
• You do not want to try to have the baby delivered vaginally in the breech position.
• An attempt to move the baby into a head-down position is not successful.
• You do not want to try to move the baby to a head-down position.

In some cases, your health care team may advise that you have both twins delivered by C-section. That might happen if the lower twin is not head down, the second twin has low or high birth weight as compared to the first twin, or if preterm labor starts.

• Landon MB, et al., eds. Normal labor and delivery. In: Gabbe's Obstetrics: Normal and Problem Pregnancies. 8th ed. Elsevier; 2021. https://www.clinicalkey.com. Accessed May 19, 2023.
• Holcroft Argani C, et al. Occiput posterior position. https://www.updtodate.com/contents/search. Accessed May 19, 2023.
• Frequently asked questions: If your baby is breech. American College of Obstetricians and Gynecologists https://www.acog.org/womens-health/faqs/if-your-baby-is-breech. Accessed May 22, 2023.
• Hofmeyr GJ. Overview of breech presentation. https://www.updtodate.com/contents/search. Accessed May 22, 2023.
• Strauss RA, et al. Transverse fetal lie. https://www.updtodate.com/contents/search. Accessed May 22, 2023.
• Chasen ST, et al. Twin pregnancy: Labor and delivery. https://www.updtodate.com/contents/search. Accessed May 22, 2023.
• Cohen R, et al. Is vaginal delivery of a breech second twin safe? A comparison between delivery of vertex and non-vertex second twins. The Journal of Maternal-Fetal & Neonatal Medicine. 2021; doi:10.1080/14767058.2021.2005569.
• Marnach ML (expert opinion). Mayo Clinic. May 31, 2023.

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Labour and Delivery Care Module: 8. Abnormal Presentations and Multiple Pregnancies

Study session 8  abnormal presentations and multiple pregnancies, introduction.

In previous study sessions of this module, you have been introduced to the definitions, signs, symptoms and stages of normal labour, and about the ‘normal’ vertex presentation of the fetus during delivery. In this study session, you will learn about the most common abnormal presentations (breech, shoulder, face or brow), their diagnostic criteria and the required actions you need to take to prevent complications developing during labour. Taking prompt action may save the life of the mother and her baby if the delivery becomes obstructed because the baby is in an abnormal presentation. We will also tell you about twin births and the complications that may result if the two babies become ‘locked’ together, preventing either of them from being born.

Learning Outcomes for Study Session 8

After studying this session, you should be able to:

8.1  Define and use correctly all of the key words printed in bold . (SAQs 8.1 and 8.2)

8.2  Describe how you would identify a fetus in the vertex presentation and distinguish this from common malpresentations and malpositions. (SAQs 8.1 and 8.2)

8.3  Describe the causes and complications for the fetus and the mother of fetal malpresentation during full term labour. (SAQ 8.3)

8.4  Describe how you would identify a multiple pregnancy and the complications that may arise. (SAQ 8.4)

8.5  Explain when and how you would refer a woman in labour due to abnormal fetal presentation or multiple pregnancy. (SAQ 8.4)

8.1  Normal and abnormal presentations

8.1.1  vertex presentation.

In about 95% of deliveries, the part of the fetus which arrives first at the mother’s pelvic brim is the highest part of the fetal head, which is called the vertex (Figure 8.1). This presentation is called the vertex presentation . Notice that the baby’s chin is tucked down towards its chest, so that the vertex is the leading part entering the mother’s pelvis. The baby’s head is said to be ‘well-flexed’ in this position.

During early pregnancy, the baby is the other way up — with its bottom pointing down towards the mother’s cervix — which is called the breech presentation . This is because during its early development, the head of the fetus is bigger than its buttocks; so in the majority of cases, the head occupies the widest cavity, i.e. the fundus (rounded top) of the uterus. As the fetus grows larger, the buttocks become bigger than the head and the baby spontaneously reverses its position, so its buttocks occupy the fundus. In short, in early pregnancy, the majority of fetuses are in the breech presentation and later in pregnancy most of them make a spontaneous transition to the vertex presentation.

8.1.2  Malpresentations

You will learn about obstructed labour in Study Session 9.

When the baby presents itself in the mother’s pelvis in any position other than the vertex presentation, this is termed an abnormal presentation, or m alpresentation . The reason for referring to this as ‘abnormal’ is because it is associated with a much higher risk of obstruction and other birth complications than the vertex presentation. The most common types of malpresentation are termed breech, shoulder, face or brow. We will discuss each of these in turn later. Notice that the baby can be ‘head-down’ but in an abnormal presentation, as in face or brow presentations, when the baby’s face or forehead (brow) is the presenting part.

8.1.3  Malposition

Although it may not be so easy for you to identify this, the baby can also be in an abnormal position even when it is in the vertex presentation. In a normal delivery, when the baby’s head has engaged in the mother’s pelvis, the back of the baby’s skull (the occiput ) points towards the front of the mother’s pelvis (the pubic symphysis ), where the two pubic bones are fused together. This orientation of the fetal skull is called the occipito-anterior position (Figure 8.2a). If the occiput (back) of the fetal skull is towards the mother’s back, this occipito-posterior position (Figure 8.2b) is a vertex malposition , because it is more difficult for the baby to be born in this orientation. The good thing is that more than 90% of babies in vertex malpositions undergo rotation to the occipito-anterior position and are delivered normally.

You learned the directional positions: anterior/in front of and posterior/behind or in the back of, in the Antenatal Care Module, Part 1, Study Session 3.

Note that the fetal skull can also be tilted to the left or to the right in either the occipito-anterior or occipito-posterior positions.

8.2  Causes and consequences of malpresentations and malpositions

In the majority of individual cases it may not be possible to identify what caused the baby to be in an abnormal presentation or position during delivery. However, the general conditions that are thought to increase the risk of malpresentation or malposition are listed below:

Multiple pregnancy is the subject of Section 8.7 of this study session. You learned about placenta previa in the Antenatal Care Module, Study Session 21.

• Abnormally increased or decreased amount of amniotic fluid
• A tumour (abnormal tissue growth) in the uterus preventing the spontaneous inversion of the fetus from breech to vertex presentation during late pregnancy
• Abnormal shape of the pelvis
• Laxity (slackness) of muscular layer in the walls of the uterus
• Multiple pregnancy (more than one baby in the uterus)
• Placenta previa (placenta partly or completely covering the cervical opening).

If the baby presents at the dilating cervix in an abnormal presentation or malposition, it will more difficult (and may be impossible) for it to complete the seven cardinal movements that you learned about in Study Sessions 3 and 5. As a result, birth is more difficult and there is an increased risk of complications, including:

You learned about PROM in Study Session 17 of the Antenatal Care Module, Part 2.

• Premature rupture of the fetal membranes (PROM)
• Premature labour
• Slow, erratic, short-lived contractions
• Uncoordinated and extremely painful contractions, with slow or no progress of labour
• Prolonged and obstructed labour, leading to a ruptured uterus (see Study Sessions 9 and 10 of this Module)
• Postpartum haemorrhage (see Study Session 11)
• Fetal and maternal distress, which may lead to the death of the baby and/or the mother.

With these complications in mind, we now turn your attention to the commonest types of malpresentation and how to recognise them.

8.3  Breech presentation

In a b reech presentation , the fetus lies with its buttocks in the lower part of the uterus, and its buttocks and/or the feet are the presenting parts during delivery. Breech presentation occurs on average in 3–4% of deliveries after 34 weeks of pregnancy.

When is the breech position the normal position for the fetus?

During early pregnancy the baby’s bottom points down towards the mother’s cervix, and its head (the largest part of the fetus at this stage of development) occupies the fundus (rounded top) of the uterus, which is the widest part of the uterine cavity.

8.3.1  Causes of breech presentation

You can see a transverse lie in Figure 8.7 later in this study session.

In the majority of cases there is no obvious reason why the fetus should present by the breech at full term. In practice, what is commonly observed is the association of breech presentation at delivery with a transverse lie earlier in the pregnancy, i.e. the fetus lies sideways across the mother’s abdomen, facing a sideways implanted placenta. It is thought that when the placenta is in front of the baby’s face, it may obstruct the normal process of inversion, when the baby turns head-down as it gets bigger during the pregnancy. As a result, the fetus turns in the other direction and ends in the breech presentation. Some other circumstances that are thought to favour a breech presentation during labour include:

• Premature labour, beginning before the baby undergoes spontanous inversion from breech to vertex presentation
• Multiple pregnancy, preventing the normal inversion of one or both babies
• Polyhydramnios: excessive amount of amniotic fluid, which makes it more difficult for the fetal head to ‘engage’ with the mother’s cervix (polyhydramnios is pronounced ‘poll-ee-hy-dram-nee-oss’. Hydrocephaly is pronounced ‘hy-droh-keff-all-ee’)
• Hydrocephaly (‘water on the brain’) i.e. an abnormally large fetal head due to excessive accumulation of fluid around the brain
• Placenta praevia
• Breech delivery in the previous pregnancy
• Abnormal formation of the uterus.

8.3.2  Diagnosis of breech presentation

On abdominal palpation the fetal head is found above the mother’s umbilicus as a hard, smooth, rounded mass, which gently ‘ballots’ (can be rocked) between your hands.

Why do you think a mass that ‘ballots’ high up in the abdomen is a sign of breech presentation? (You learned about this in Study Session 11 of the Antenatal Care Module.)

The baby’s head can ‘rock’ a little bit because of the flexibility of the baby’s neck, so if there is a rounded, ballotable mass above the mother’s umbilicus it is very likely to be the baby’s head. If the baby was ‘bottom-up’ (vertex presentation) the whole of its back will move of you try to rock the fetal parts at the fundus (Figure 8.3).

Once the fetus has engaged and labour has begun, the breech baby’s buttocks can be felt as soft and irregular on vaginal examination. They feel very different to the relatively hard rounded mass of the fetal skull in a vertex presentation. When the fetal membranes rupture, the buttocks and/or feet can be felt more clearly. The baby’s anus may be felt and fresh thick, dark meconium may be seen on your examining finger. If the baby’s legs are extended, you may be able to feel the external genitalia and even tell the sex of the baby before it is born.

8.3.3  Types of breech presentation

There are three types of breech presentation, as illustrated in Figure 8.4. They are:

• Complete breech is characterised by flexion of the legs at both hips and knee joints, so the legs are bent underneath the baby.
• Frank breech is the commonest type of breech presentation, and is characterised by flexion at the hip joints and extension at the knee joints, so both the baby’s legs point straight upwards.
• Footling breech is when one or both legs are extended at the hip and knee joint and the baby presents ‘foot first’.

8.3.4  Risks of breech presentation

Regardless of the type of breech presentation, there are significant associated risks to the baby. They include:

• The fetal head gets stuck (arrested) before delivery
• Labour becomes obstructed when the fetus is disproportionately large for the size of the maternal pelvis
• Cord prolapse may occur, i.e. the umbilical cord is pushed out ahead of the baby and may get compressed against the wall of the cervix or vagina
• Premature separation of the placenta (placental abruption)
• Birth injury to the baby, e.g. fracture of the arms or legs, nerve damage, trauma to the internal organs, spinal cord damage, etc.

A breech birth may also result in trauma to the mother’s birth canal or external genitalia through being overstretched by the poorly fitting fetal parts.

Cord prolapse in a normal (vertex) presentation was illustrated in Study Session 17 of the Antenatal Care Module, and placental abruption was covered in Study Session 21.

What will be the effect on the baby if it gets stuck, the labour is obstructed, the cord prolapses, or placental abruption occurs?

The result will be hypoxia , i.e. it will be deprived of oxygen, and may suffer permanent brain damage or die.

You learned about the causes and consequences of hypoxia in the Antenatal Care Module.

8.4  Face presentation

Face presentation occurs when the baby’s neck is so completely extended (bent backwards) that the occiput at the back of the fetal skull touches the baby’s own spine (see Figure 8.5). In this position, the baby’s face will present to you during delivery.

Refer the mother if a baby in the chin posterior face presentation does not rotate and the labour is prolonged.

The incidence of face presentation is about 1 in 500 pregnancies in full term labours. In Figure 8.5, you can see how flexed the head is at the neck. Babies who present in the ‘chin posterior’ position (on the right in Figure 8.5) usually rotate spontaneously during labour, and assume the ‘chin anterior’ position, which makes it easier for them to be born. However, they are unlikely to be delivered vaginally if they fail to undergo spontaneous rotation to the chin anterior position, because the baby’s chin usually gets stuck against the mother’s sacrum (the bony prominence at the back of her pelvis). A baby in this position will have to be delivered by caesarean surgery.

8.4.1  Causes of face presentation

The causes of face presentation are similar to those already described for breech births:

• Laxity (slackness) of the uterus after many previous full-term pregnancies
• Multiple pregnancy
• Polyhydramnios (excessive amniotic fluid)
• Congenital abnormality of the fetus (e.g. anencephaly, which means no or incomplete skull bones)
• Abnormal shape of the mother’s pelvis.

8.4.2  Diagnosis of face presentation

Face presentation may not be easily detected by abdominal palpation, especially if the chin is in the posterior position. On abdominal examination, you may feel irregular shapes, formed because the fetal spine is curved in an ‘S’ shape. However, on vaginal examination, you can detect face presentation because:

• The presenting part will be high, soft and irregular.
• When the cervix is sufficiently dilated, you may be able to feel parts of the face, such as the orbital ridges above the eyes, the nose or mouth, gums, or bony chin.
• If the membranes are ruptured, the baby may suck your examining finger!

But as labour progresses, the baby’s face becomes o edematous (swollen with fluid), making it more difficult to distinguish from the soft shape you will feel in a breech presentation.

8.4.3  Complications of face presentation

Complications for the fetus include:

• Obstructed labour and ruptured uterus
• Cord prolapse
• Facial bruising
• Cerebral haemorrhage (bleeding inside the fetal skull).

8.5  Brow presentation

In brow presentation , the baby’s head is only partially extended at the neck (compare this with face presentation), so its brow (forehead) is the presenting part (Figure 8.6). This presentation is rare, with an incidence of 1 in 1000 deliveries at full term.

8.5.1  Possible causes of brow presentation

You have seen all of these factors before, as causes of other malpresentations:

• Lax uterus due to repeated full term pregnancy
• Polyhydramnios

8.5.2  Diagnosis of brow presentation

Brow presentation is not usually detected before the onset of labour, except by very experienced birth attendants. On abdominal examination, the head is high in the mother’s abdomen, appears unduly large and does not descend into the pelvis, despite good uterine contractions. On vaginal examination, the presenting part is high and may be difficult to reach. You may be able to feel the root of the nose, eyes, but not the mouth, tip of the nose or chin. You may also feel the anterior fontanel, but a large caput (swelling) towards the front of the fetal skull may mask this landmark if the woman has been in labour for some hours.

Recall the appearance of a normal caput over the posterior fontanel shown in Figure 4.4 earlier in this Module.

8.5.3  Complications of brow presentation

The complications of brow presentation are much the same as for other malpresentations:

• Cerebral haemorrhage.

Which are you more likely to encounter — face or brow presentations?

Face presentation, which occurs in 1 in 500 full term labours. Brow presentation is more rare, at 1 in 1,000 full term labours.

8.6  Shoulder presentation

Shoulder presentation is rare at full term, but may occur when the fetus lies transversely across the uterus (Figure 8.7), if it stopped part-way through spontaneous inversion from breech to vertex, or it may lie transversely from early pregnancy. If the baby lies facing upwards, its back may be the presenting part; if facing downwards its hand may emerge through the cervix. A baby in the transverse position cannot be born through the vagina and the labour will be obstructed. Refer babies in shoulder presentation urgently.

8.6.1  Causes of shoulder presentation

Causes of shoulder presentation could be maternal or fetal factors.

Maternal factors include:

• Lax abdominal and uterine muscles: most often after several previous pregnancies
• Uterine abnormality
• Contracted (abnormally narrow) pelvis.

Fetal factors include:

• Preterm labour
• Placenta previa.

What do ‘placenta previa’ and ‘polyhydramnios’ indicate?

Placenta previa is when the placenta is partly or completely covering the cervical opening. Polyhydramnios is an excess of amniotic fluid. They are both potential causes of malpresentation.

8.6.2  Diagnosis of shoulder presentation

On abdominal palpation, the uterus appears broader and the height of the fundus is less than expected for the period of gestation, because the fundus is not occupied by either the baby’s head or buttocks. You can usually feel the head on one side of the mother’s abdomen. On vaginal examination, in early labour, the presenting part may not be felt, but when the labour is well progressed, you may feel the baby’s ribs. When the shoulder enters the pelvic brim, the baby’s arm may prolapse and become visible outside the vagina.

8.6.3  Complications of shoulder presentation

Complications include:

• Trauma to a prolapsed arm
• Fetal hypoxia and death.

Remember that a shoulder presentation means the baby cannot be born through the vagina; if you detect it in a woman who is already in labour, refer her urgently to a higher health facility.

8.7  Multiple pregnancy

In this section, we turn to the subject of multiple pregnancy , when there is more than one fetus in the uterus. More than 95% of multiple pregnancies are twins (two fetuses), but there can also be triplets (three fetuses), quadruplets (four fetuses), quintuplets (five fetuses), and other higher order multiples with a declining chance of occurrence. The spontaneous occurrence of twins varies by country : it is lowest in East Asia n countries like Japan and China (1 out of 1000 pregnancies are fraternal or non-identical twins), and highest in black Africans , particularly in Nigeria , where 1 in 20 pr egnancies are fraternal twins. In general, compared to single babies, multiple pregnancies are highly associated with early pregnancy loss and high perinatal mortality, mainly due to prematurity.

8.7.1  Types of twin pregnancy

Twins may be identical (monozygotic) or non-identical and fraternal (dizigotic). Monozygotic twins develop from a single fertilised ovum (the zygote), so they are always the same sex and they share the same placenta . By contrast, dizygotic twins develop from two different zygotes, so they can have the same or different sex, and they have separate placenta s . Figure 8.8 shows the types of twin pregnancy and the processes by which they are formed.

8.7.2  Diagnosis of twin pregnancy

On abdominal examination you may notice that:

• The size of the uterus is larger than the expected for the period for gestation.
• The uterus looks round and broad, and fetal movement may be seen over a large area. (The shape of the uterus at term in a singleton pregnancy in the vertex presentation appears heart-shaped rounder at the top and narrower at the bottom.)
• Two heads can be felt.
• Two fetal heart beats may be heard if two people listen at the same time, and they can detect at least 10 beats different (Figure 8.6).
• Ultrasound examination can make an absolute diagnosis of twin pregnancy.

8.7.3  Consequences of twin pregnancy

Women who are pregnant with twins are more prone to suffer with the minor disorders of pregnancy, like morning sickness, nausea and heartburn. Twin pregnancy is one cause of hyperemesis gravidarum (persistent, severe nausea and vomiting). Mothers of twins are also more at risk of developing iron and folate-deficiency anaemia during pregnancy.

Can you suggest why anaemia is a greater risk in multiple pregnancies?

The mother has to supply the nutrients to feed two (or more) babies; if she is not getting enough iron and folate in her diet, or through supplements, she will become anaemic.

Other complications include the following:

• Pregnancy-related hypertensive disorders like pre-eclampsia and eclampsia are more common in twin pregnancies.
• Pressure symptoms may occur in late pregnancy due to the increased weight and size of the uterus.
• Labour often occurs spontaneously before term, with p remature delivery or premature rupture of membranes (PROM) .
• Respiratory deficit ( shortness of breath, because of fast growing uterus) is another common problem.

Twin babies may be small in comparison to their gestational age and more prone to the complications associated with low birth weight (increased vulnerability to infection, losing heat, difficulty breastfeeding).

You will learn about low birth weight babies in detail in the Postnatal Care Module.

• Malpresentation is more common in twin pregnancies, and they may also be ‘locked’ at the neck with one twin in the vertex presentation and the other in breech. The risks associated with malpresentations already described also apply: prolapsed cord, poor uterine contraction, prolonged or obstructed labour, postpartum haemorrhage, and fetal hypoxia and death.
• Conjoined twins (fused twins, joined at the head, chest, or abdomen, or through the back) may also rarely occur.

8.8  Management of women with malpresentation or multiple pregnancy

As you have seen in this study session, any presentation other than vertex has its own dangers for the mother and baby. For this reason, all women who develop abnormal presentation or multiple pregnancy should ideally have skilled care by senior health professionals in a health facility where there is a comprehensive emergency obstetric service. Early detection and referral of a woman in any of these situations can save her life and that of her baby.

What can you do to reduce the risks arising from malpresentation or multiple pregnancy in women in your care?

During focused antenatal care of the pregnant women in your community, at every visit after 36 weeks of gestation you should check for the presence of abnormal fetal presentation. If you detect abnormal presentation or multiple pregnancy, you should refer the woman before the onset of labour.

Summary of Study Session 8

In Study Session 8, you learned that:

• During early pregnancy, babies are naturally in the breech position, but in 95% of cases they spontaneously reverse into the vertex presentation before labour begins.
• Malpresentation or malposition of the fetus at full term increases the risk of obstructed labour and other birth complications.
• Common causes of malpresentations/malpositions include: excess amniotic fluid, abnormal shape and size of the pelvis; uterine tumour; placenta praevia; slackness of uterine muscles (after many previous pregnancies); or multiple pregnancy.
• Common complications include: premature rupture of membranes, premature labour, prolonged/obstructed labour; ruptured uterus; postpartum haemorrhage; fetal and maternal distress which may lead to death.
• Vertex malposition is when the fetal head is in the occipito-posterior position — i.e. the back of the fetal skull is towards the mother’s back instead of pointing towards the front of the mother’s pelvis. 90% of vertex malpositions rotate and deliver normally.
• Breech presentation (complete, frank or footling) is when the baby’s buttocks present during labour. It occurs in 3–4% of labours after 34 weeks of pregnancy and may lead to obstructed labour, cord prolapse, hypoxia, premature separation of the placenta, birth injury to the baby or to the birth canal.
• Face presentation is when the fetal head is bent so far backwards that the face presents during labour. It occurs in about 1 in 500 full term labours. ‘Chin posterior’ face presentations usually rotate spontaneously to the ‘chin anterior’ position and deliver normally. If rotation does not occur, a caesarean delivery is likely to be necessary.
• Brow presentation is when the baby’s forehead is the presenting part. It occurs in about 1 in 1000 full term labours and is difficult to detect before the onset of labour. Caesarean delivery is likely to be necessary.
• Shoulder presentation occurs when the fetal lie during labour is transverse. Once labour is well progressed, vaginal examination may feel the baby’s ribs, and an arm may sometimes prolapse. Caesarean delivery is always required unless a doctor or midwife can turn the baby head-down.
• Multiple pregnancies are always at high risk of malpresentation. Mothers need greater antenatal care, and twins are more prone to complications associated with low birth weight and prematurity.
• Any presentation other than vertex after 34 weeks of gestation is considered as high risk to the mother and to her baby. Do not attempt to turn a malpresenting or malpositioned baby! Refer the mother for emergency obstetric care.

Self-Assessment Questions (SAQs) for Study Session 8

Now that you have completed this study session, you can assess how well you have achieved its Learning Outcomes by answering the following questions. Write your answers in your Study Diary and discuss them with your Tutor at the next Study Support Meeting. You can check your answers with the Notes on the Self-Assessment Questions at the end of this Module.

SAQ 8.1 (tests Learning Outcomes 8.1, 8.2 and 8.4)

Which of the following definitions are true and which are false? Write down the correct definition for any which you think are false.

A  Fundus — the ‘rounded top’ and widest cavity of the uterus.

B  Complete breech — where the legs are bent at both hips and knee joints and are folded underneath the baby.

C  Frank breech — where the breech is so difficult to treat that you have to be very frank and open with the mother about the difficulties she will face in the birth.

D  Footling breech — when one or both legs are extended so that the baby presents ‘foot first’.

E  Hypoxia — the baby gets too much oxygen.

F  Multiple pregnancy — when a mother has had many babies previously.

G  Monozygotic twins — develop from a single fertilised ovum (the zygote). They can be different sexes but they share the same placenta.

H  Dizygotic twins — develop from two zygotes. They have separate placentas, and can be of the same sex or different sexes.

A is true.  The fundus is the ‘rounded top’ and widest cavity of the uterus.

B is true.  Complete breech is where the legs are bent at both hips and knee joints and are folded underneath the baby.

C is false . A frank breech is the most common type of breech presentation and is when the baby’s legs point straight upwards (see Figure 8.4).

D is true.   A footling breech is when one or both legs are extended so that the baby presents ‘foot first’.

E is false .  Hypoxia is when the baby is deprived of oxygen and risks permanent brain damage or death.

F is false.   Multiple pregnancy is when there is more than one fetus in the uterus.

G is false.   Monozygotic twins develop from a single fertilised ovum (the zygote), and they are always the same sex , as well as sharing the same placenta.

H is true.  Dizygotic twins develop from two zygotes, have separate placentas, and can be of the same or different sexes.

SAQ 8.2 (tests Learning Outcomes 8.1 and 8.2)

What are the main differences between normal and abnormal fetal presentations? Use the correct medical terms in bold in your explanation.

In a normal presentation, the vertex (the highest part of the fetal head) arrives first at the mother’s pelvic brim, with the occiput (the back of the baby’s skull) pointing towards the front of the mother’s pelvis (the pubic symphysis ).

Abnormal presentations are when there is either a vertex malposition (the occiput of the fetal skull points towards the mother’s back instead towards of the pubic symphysis), or a malpresentation (when anything other than the vertex is presenting): e.g. breech presentation (buttocks first); face presentation (face first); brow presentation (forehead first); and shoulder presentation (transverse fetal).

SAQ 8.3 (tests Learning Outcomes 8.3 and 8.5)

• a. List the common complications of malpresentations or malposition of the fetus at full term.
• b. What action should you take if you identify that the fetus is presenting abnormally and labour has not yet begun?
• c. What should you not attempt to do?
• a. The common complications of malpresentation or malposition of the fetus at full term include: premature rupture of membranes, premature labour, prolonged/obstructed labour; ruptured uterus; postpartum haemorrhage; fetal and maternal distress which may lead to death.
• b. You should refer the mother to a higher health facility – she may need emergency obstetric care.
• c. You should not attempt to turn the baby by hand. This should only be attempted by a specially trained doctor or midwife and should only be done at a health facility.

SAQ 8.4 (tests Learning Outcomes 8.4 and 8.5)

A pregnant woman moves into your village who is already at 37 weeks gestation. You haven’t seen her before. She tells you that she gave birth to twins three years ago and wants to know if she is having twins again this time.

• a. How would you check this?
• b. If you diagnose twins, what would you do to reduce the risks during labour and delivery?
• Is the uterus larger than expected for the period of gestation?
• What is its shape – is it round (indicative of twins) or heart-shaped (as in a singleton pregnancy)?
• Can you feel more than one head?
• Can you hear two fetal heartbeats (two people listening at the same time) with at least 10 beats difference?
• If there is access to a higher health facility, and you are still not sure, try and get the woman to it for an ultrasound scan.
• Be extra careful to check that the mother is not anaemic.
• Encourage her to rest and put her feet up to reduce the risk of increased blood pressure or swelling in her legs and feet.
• Be alert to the increased risk of pre-eclampsia.
• Expect her to go into labour before term, and be ready to get her to the health facility before she goes into labour, going with her if at all possible.
• Get in early touch with that health facility to warn them to expect a referral from you.
• Make sure that transport is ready to take her to a health facility when needed.

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Breech, posterior, transverse lie: What position is my baby in?

Fetal presentation, or how your baby is situated in your womb at birth, is determined by the body part that's positioned to come out first, and it can affect the way you deliver. At the time of delivery, 97 percent of babies are head-down (cephalic presentation). But there are several other possibilities, including feet or bottom first (breech) as well as sideways (transverse lie) and diagonal (oblique lie).

Fetal presentation and position

During the last trimester of your pregnancy, your provider will check your baby's presentation by feeling your belly to locate the head, bottom, and back. If it's unclear, your provider may do an ultrasound or an internal exam to feel what part of the baby is in your pelvis.

Fetal position refers to whether the baby is facing your spine (anterior position) or facing your belly (posterior position). Fetal position can change often: Your baby may be face up at the beginning of labor and face down at delivery.

Here are the many possibilities for fetal presentation and position in the womb.

Medical illustrations by Jonathan Dimes

Head down, facing down (anterior position)

A baby who is head down and facing your spine is in the anterior position. This is the most common fetal presentation and the easiest position for a vaginal delivery.

This position is also known as "occiput anterior" because the back of your baby's skull (occipital bone) is in the front (anterior) of your pelvis.

Head down, facing up (posterior position)

In the posterior position , your baby is head down and facing your belly. You may also hear it called "sunny-side up" because babies who stay in this position are born facing up. But many babies who are facing up during labor rotate to the easier face down (anterior) position before birth.

Posterior position is formally known as "occiput posterior" because the back of your baby's skull (occipital bone) is in the back (posterior) of your pelvis.

Frank breech

In the frank breech presentation, both the baby's legs are extended so that the feet are up near the face. This is the most common type of breech presentation. Breech babies are difficult to deliver vaginally, so most arrive by c-section .

Some providers will attempt to turn your baby manually to the head down position by applying pressure to your belly. This is called an external cephalic version , and it has a 58 percent success rate for turning breech babies. For more information, see our article on breech birth .

Complete breech

A complete breech is when your baby is bottom down with hips and knees bent in a tuck or cross-legged position. If your baby is in a complete breech, you may feel kicking in your lower abdomen.

Incomplete breech

In an incomplete breech, one of the baby's knees is bent so that the foot is tucked next to the bottom with the other leg extended, positioning that foot closer to the face.

Single footling breech

In the single footling breech presentation, one of the baby's feet is pointed toward your cervix.

Double footling breech

In the double footling breech presentation, both of the baby's feet are pointed toward your cervix.

Transverse lie

In a transverse lie, the baby is lying horizontally in your uterus and may be facing up toward your head or down toward your feet. Babies settle this way less than 1 percent of the time, but it happens more commonly if you're carrying multiples or deliver before your due date.

If your baby stays in a transverse lie until the end of your pregnancy, it can be dangerous for delivery. Your provider will likely schedule a c-section or attempt an external cephalic version , which is highly successful for turning babies in this position.

Oblique lie

In rare cases, your baby may lie diagonally in your uterus, with his rump facing the side of your body at an angle.

Like the transverse lie, this position is more common earlier in pregnancy, and it's likely your provider will intervene if your baby is still in the oblique lie at the end of your third trimester.

Was this article helpful?

What to know if your baby is breech

What's a sunny-side up baby?

How your twins’ fetal positions affect labor and delivery

What happens to your baby right after birth

BabyCenter's editorial team is committed to providing the most helpful and trustworthy pregnancy and parenting information in the world. When creating and updating content, we rely on credible sources: respected health organizations, professional groups of doctors and other experts, and published studies in peer-reviewed journals. We believe you should always know the source of the information you're seeing. Learn more about our editorial and medical review policies .

Ahmad A et al. 2014. Association of fetal position at onset of labor and mode of delivery: A prospective cohort study. Ultrasound in obstetrics & gynecology 43(2):176-182. https://www.ncbi.nlm.nih.gov/pubmed/23929533 Opens a new window [Accessed September 2021]

Gray CJ and Shanahan MM. 2019. Breech presentation. StatPearls.  https://www.ncbi.nlm.nih.gov/books/NBK448063/ Opens a new window [Accessed September 2021]

Hankins GD. 1990. Transverse lie. American Journal of Perinatology 7(1):66-70.  https://www.ncbi.nlm.nih.gov/pubmed/2131781 Opens a new window [Accessed September 2021]

Medline Plus. 2020. Your baby in the birth canal. U.S. National Library of Medicine. https://medlineplus.gov/ency/article/002060.htm Opens a new window [Accessed September 2021]

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Vertex Presentation : Types, Positions, Complications and Risks

Do not ignore your symptoms!

Find out what could be causing them

Overview 

When babies are about to enter the world, they are either in a vertex, breech, or transverse position. A vertex position means the baby is head-down in the pelvic region, which is the position a baby is required to be during vaginal delivery. 

This blog talks about the vertex position, complications, and the other types of positions the baby can be during delivery. 

What is the vertex position? 

As mentioned earlier, a vertex position is a baby’s position during vaginal delivery. The baby moves into the vertex position  between the 33 rd – 36 th week of pregnancy. In this position, the baby’s head comes out first through the vagina during delivery. However, it is vital to know that the baby can present with other positions like breech (feet-first position) or transverse (lying sideways) position. In such cases, the healthcare provider may suggest alternate birth plans to deliver the baby safely.   

How is a baby delivered in the vertex position?  

When a baby is in a vertex position, it moves through the birth canal and comes out through the vagina. Unlike other mammals that have wider birth canals, humans have smaller ones. Due to the tight space in the birth canal, the baby tends to flex their heads in different ways to fit into the area and enter the world. However, the chances of the baby changing position at the last minute reduce drastically when the baby’s head fits inside the birth canal. The baby can switch to a vertex position anytime during delivery even if it is in a breech or transverse position.

When to seek medical advice?

A pregnant woman can seek medical advice to clear any doubts or clarifications.

What are the other positions a baby may lie in the womb?  

As already mentioned, unborn babies may also assume breech or transverse positions in the womb. The following gives a detailed explanation of both.

Breech Position

In this position, the babies lie in the womb pointing their feet or buttocks toward the vagina of the mother. If the baby stays in a breech position even after 36 weeks of pregnancy, the healthcare provider may try External Cephalic Version (ECV) on the mother. ECV refers to external pressure on the belly to change the baby’s position to a vertex. This procedure is painful for the mother, but it is the safest way to keep the baby in place. In almost 50% of the cases, ECV works and assists the baby in moving into a vertex position. 

In case of vaginal bleeding , the irregular heartbeat of the baby, broken water, or multiple pregnancies, ECV is not recommended. Also, ECV should not be performed if the baby is bigger or smaller than usual, if the placenta is low or if the mother develops high blood pressure and organ damage. The healthcare provider may recommend C-section to deliver the baby in such cases. 

Transverse Position

The baby is lying across the uterus during delivery. The doctors may recommend an ECV procedure. If ECV fails, the healthcare provider may deliver the baby through a C-section .

Can complications happen even when the baby is in the vertex position? 

Even though the vertex position is the correct way a baby should lie during delivery, there are chances of complications. If the baby weighs more than 4.5 kg, it becomes challenging for the baby to manoeuvre out of the birth canal. The shoulders of heavy babies may face trouble moving down the canal. For such babies, doctors regularly conduct checks and are extra cautious during prenatal visits and at the time of birth. For babies above 5 kg, they may recommend alternate delivery options to avoid trauma for both the baby and the mother.  

What are the risks associated with the Breech and Transverse position of the baby? 

Breech and transverse positions can lead to many complications, such as the following:  

ECV issues : While the healthcare provider performs ECV to shift the baby’s position into a vertex position, it may rupture the amniotic sac or tear the placenta. Sometimes it may change the baby’s heartbeat or may induce early labour.  

Problems with breech birth : In the breech position, the baby isn’t able to push the cervical muscles of the mother to come out. Their shoulders or heads may get stuck or impaled by the mother’s pelvis. Also, the umbilical cord may enter the vagina before the baby, reducing blood and oxygen flow to the baby.    

Conclusion 

Vertex position is the right way a baby should lie in the womb during delivery. It doesn’t mean that vertex position does not cause complications. It is crucial to seek expert advice during pregnancy to clarify doubts and address all concerns.  

Frequently Asked Questions (FAQs)

Will the baby turn after being in a vertex position .

Even when the baby is in the proper vertex position, there are chances of them turning to other positions. Expectant mothers with excess amniotic fluid may be a risk of a vertex-positioned baby suddenly becoming breech. Consult the healthcare provider and ask what can be done about keeping the baby in the proper position until delivery.  

How to know if a pregnant woman is having a vertex-positioned baby? 

All healthcare professionals are trained to feel the baby’s position with their hands. This method is known as Leopold’s moves, and they may help find if the baby has a positioned vertex. An ultrasound test also helps precisely find and confirm the baby’s position.  

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Fetal Malpresentation and Malposition

Fetal presentation describes which part of the fetus will enter through the cervix Cervix The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Externally, the cervix is lined by stratified squamous cells; however, the cervical canal is lined by columnar epithelium. Uterus, Cervix, and Fallopian Tubes: Anatomy first, while position is the orientation Orientation Awareness of oneself in relation to time, place and person. Psychiatric Assessment of the fetus compared to the maternal bony pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 "hip" bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy . Presentations include vertex (the fetal occiput will present through the cervix Cervix The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Externally, the cervix is lined by stratified squamous cells; however, the cervical canal is lined by columnar epithelium. Uterus, Cervix, and Fallopian Tubes: Anatomy first), face, brow, shoulder, and breech. If a fetal limb is presenting next to the presenting part (e.g., the hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy is next to the head), this is known as a compound presentation. Malpresentation refers to any presentation other than vertex, with the most common being breech presentations. Vaginal delivery of a breech infant increases the risk for head entrapment and hypoxia Hypoxia Sub-optimal oxygen levels in the ambient air of living organisms. Ischemic Cell Damage , so, especially in the United States, mothers are generally offered a procedure to help manually rotate the baby to a head-down position instead (known as an external cephalic version) or a planned cesarean delivery Cesarean Delivery Cesarean delivery (CD) is the operative delivery of ≥ 1 infants through a surgical incision in the maternal abdomen and uterus. Cesarean deliveries may be indicated for a number of either maternal or fetal reasons, most commonly including fetal intolerance to labor, arrest of labor, a history of prior uterine surgery, fetal malpresentation, and placental abnormalities. Cesarean Delivery .

Last updated: Feb 14, 2023

Fetal Lie and Presentation

Presenting diameter, management of cephalic and compound presentations, risks and management of breech and transverse presentations.

Share this concept:

• The “presenting part” refers to the part of the baby that will come through the cervix Cervix The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Externally, the cervix is lined by stratified squamous cells; however, the cervical canal is lined by columnar epithelium. Uterus, Cervix, and Fallopian Tubes: Anatomy first. 
• The position refers to how that body part (and thus the baby) is oriented within the maternal pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy . 
• The uterine fundus Fundus The superior portion of the body of the stomach above the level of the cardiac notch. Stomach: Anatomy is typically roomier, so babies tend to orient themselves head down so that their body and limbs occupy the larger portion of the uterus Uterus The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The uterus has a thick wall made of smooth muscle (the myometrium) and an inner mucosal layer (the endometrium). The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Uterus, Cervix, and Fallopian Tubes: Anatomy .

Clinical relevance

• The maternal pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy has a diameter of about 10 cm, through which the fetus must pass.
• The presentation and position of the fetus will determine how wide the fetus is (known as the “presenting fetal diameter”) as it attempts to pass through the maternal pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy .
• Certain presentation/positions are more difficult (or even impossible) to pass through the pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy because of their large presenting diameter.
• Knowledge of the presentation and position are required to safely manage labor and delivery.

Risk factors for fetal malpresentation

• Multiparity (which can result in lax abdominal walls)
• Multiple gestations (e.g., twins)
• Prematurity Prematurity Neonatal Respiratory Distress Syndrome
• Uterine abnormalities (e.g., leiomyomas, uterine septa)
• Narrow pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy shapes
• Fetal anomalies (e.g., hydrocephalus Hydrocephalus Excessive accumulation of cerebrospinal fluid within the cranium which may be associated with dilation of cerebral ventricles, intracranial. Subarachnoid Hemorrhage )
• Placental anomalies (e.g.,   placenta previa Placenta Previa Abnormal placentation in which the placenta implants in the lower segment of the uterus (the zone of dilation) and may cover part or all of the opening of the cervix. It is often associated with serious antepartum bleeding and premature labor. Placental Abnormalities , in which the placenta Placenta A highly vascularized mammalian fetal-maternal organ and major site of transport of oxygen, nutrients, and fetal waste products. It includes a fetal portion (chorionic villi) derived from trophoblasts and a maternal portion (decidua) derived from the uterine endometrium. The placenta produces an array of steroid, protein and peptide hormones (placental hormones). Placenta, Umbilical Cord, and Amniotic Cavity covers the internal cervical os)
• Polyhydramnios Polyhydramnios Polyhydramnios is a pathological excess of amniotic fluid. Common causes of polyhydramnios include fetal anomalies, gestational diabetes, multiple gestations, and congenital infections. Patients are often asymptomatic but may present with dyspnea, extremity swelling, or abdominal distention. Polyhydramnios (too much fluid)
• Oligohydramnios Oligohydramnios Oligohydramnios refers to amniotic fluid volume less than expected for the current gestational age. Oligohydramnios is diagnosed by ultrasound and defined as an amniotic fluid index (AFI) of ‰¤ 5 cm or a single deep pocket (SDP) of Oligohydramnios (not enough fluid)
• Malpresentation in a previous pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care

Epidemiology

Prevalence Prevalence The total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time. Measures of Disease Frequency rates for different malpresentations at term:

• Vertex presentation, occiput posterior position: 1 in 19 deliveries
• Breech presentation: 1 in 33 deliveries
• Face presentation: 1 in 600–800 deliveries
• Transverse lie: 1 in 833 deliveries
• Compound presentation: 1 in 1500 deliveries 

Related videos

Fetal lie is how the long axis of the fetus is oriented in relation to the mother. Possible lies include:

• Longitudinal: fetus and mother have the same vertical axis (their spines are parallel).
• Transverse: fetal vertical axis is at a 90-degree angle to mother’s vertical axis (their spines are perpendicular).
• Oblique: fetal vertical axis is at a 45-degree angle to mother’s vertical axis (unstable, and will resolve to longitudinal or transverse during labor).

Presentation

Presentation describes which body part of the fetus will pass through the cervix Cervix The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Externally, the cervix is lined by stratified squamous cells; however, the cervical canal is lined by columnar epithelium. Uterus, Cervix, and Fallopian Tubes: Anatomy first. Presentations include:

• Cephalic: head down
• Breech: bottom/feet down
• Transverse presentation: shoulder 
• Compound presentation: an extremity presents alongside the primary presenting part

Cephalic presentations

Cephalic presentations can be categorized as:

• Vertex presentation: chin Chin The anatomical frontal portion of the mandible, also known as the mentum, that contains the line of fusion of the two separate halves of the mandible (symphysis menti). This line of fusion divides inferiorly to enclose a triangular area called the mental protuberance. On each side, inferior to the second premolar tooth, is the mental foramen for the passage of blood vessels and a nerve. Melasma flexed, with the occipital Occipital Part of the back and base of the cranium that encloses the foramen magnum. Skull: Anatomy fontanel as the presenting part
• Face presentation
• Brow presentation: forehead Forehead The part of the face above the eyes. Melasma is the presenting part

Vertex presentation

Face presentation (mentum anterior position)

Brow presentation (mentum posterior position)

Breech presentations

Breech presentations can be categorized as:

• Frank breech: bottom down, legs extended (50%–70%) 
• Complete breech: bottom down, hips and knees both flexed
• Incomplete breech: 1 or both hips not completely flexed
• Footling breech: feet down

Breech presentations: Frank (bottom down, legs extended), complete (bottom down, hips and knees both flexed), and footling (feet down) breech presentations

Transverse and compound presentations

• Uncommon, but when they occur, the presenting fetal part is the shoulder.
• If the cervix Cervix The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Externally, the cervix is lined by stratified squamous cells; however, the cervical canal is lined by columnar epithelium. Uterus, Cervix, and Fallopian Tubes: Anatomy begins dilating, the arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy may prolapse through the cervix Cervix The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Externally, the cervix is lined by stratified squamous cells; however, the cervical canal is lined by columnar epithelium. Uterus, Cervix, and Fallopian Tubes: Anatomy .
• In compound presentations, the most common situation is a hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy or arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy presenting with the head.

Shoulder presentation (transverse lie)

Neglected shoulder presentation resulting in arm prolapse during labor

Vertex presentation with a compound hand

Fetal malpresentation

• Any presentation other than vertex
• Clinically, this means breech, face, brow, and shoulder presentations.

Position describes the relation of the fetal presenting part to the maternal bony pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy .

Vertex positions

Positions for vertex presentations describe the position of the fetal occiput .

• Identified on cervical exam as the area in the midline between the anterior and posterior fontanelles Fontanelles Physical Examination of the Newborn
• Anterior, posterior, or transverse in relation to the maternal pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy
• Being on the maternal right or left
• Right or left occiput anterior
• Right or left occiput posterior
• Right or left occiput transverse
• Direct occiput anterior or posterior
• The most common positions (and easiest for vaginal delivery) are occiput anterior.

Overview of different vertex positions LOA: left occiput anterior LOP: left occiput posterior LOT: left occiput transverse OA occiput anterior OP: occiput posterior ROA: right occiput anterior ROP: right occiput posterior ROT: right occiput transverse

Face and brow positions

Positions for face and brow presentations describe the position of the chin Chin The anatomical frontal portion of the mandible, also known as the mentum, that contains the line of fusion of the two separate halves of the mandible (symphysis menti). This line of fusion divides inferiorly to enclose a triangular area called the mental protuberance. On each side, inferior to the second premolar tooth, is the mental foramen for the passage of blood vessels and a nerve. Melasma .

• The chin Chin The anatomical frontal portion of the mandible, also known as the mentum, that contains the line of fusion of the two separate halves of the mandible (symphysis menti). This line of fusion divides inferiorly to enclose a triangular area called the mental protuberance. On each side, inferior to the second premolar tooth, is the mental foramen for the passage of blood vessels and a nerve. Melasma is referred to as the mentum.
• Right or left mentum anterior
• Right or left mentum posterior
• Right or left mentum transverse
• Direct mentum anterior or posterior

Face presentation (mentum posterior position)

Breech and shoulder positions

• Positions for breech presentations describe the position of the sacrum Sacrum Five fused vertebrae forming a triangle-shaped structure at the back of the pelvis. It articulates superiorly with the lumbar vertebrae, inferiorly with the coccyx, and anteriorly with the ilium of the pelvis. The sacrum strengthens and stabilizes the pelvis. Vertebral Column: Anatomy . Similar to other presentations, they include anterior, posterior, and transverse and right, left, and direct.
• Dorso-superior (back up)
• Dorso-inferior (back down)

Dorso-inferior shoulder presentation

Dorso-superior shoulder presentation

Attitude and asynclitism

• Attitude: amount of flexion Flexion Examination of the Upper Limbs or extension Extension Examination of the Upper Limbs of the fetal head
• Lateral deflection of the sagittal Sagittal Computed Tomography (CT) suture to 1 side or the other
• Mild degrees of asynclitism are normal.
• More severe asynclitism increases the presenting fetal diameter and makes it more difficult for the fetal head to pass through the maternal pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy .

Fetal malposition

• Commonly refers to any position other than right occiput anterior, left occiput anterior, or direct occiput anterior
• All nonvertex presentations are also malpositioned.
• The terms fetal malpresentation and fetal malposition are often used interchangeably.
• The presenting diameter refers to the width of the presenting part.
• The maternal pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy is about 10 cm at its narrowest point; the infant must orient itself so that it can fit through.
• Most commonly, the infant will move into a cephalic, vertex presentation, in 1 of the occiput anterior positions → presents the narrowest diameter
• Vertex presentation: suboccipitobregmatic diameter, approximately 9.5 cm
• Vertex presentation with deflexed head: occipitofrontal diameter, approximately 11.5 cm
• Brow presentation: occipitomental diameter, approximately 13 cm
• Face presentation: submentobregmatic diameter, approximately 9.5 cm

Diameters of the fetal head

Comparison of presentation, attitude, and presenting diameter

How to establish lie, presentation, and position

Delivery is managed differently depending on the presentation and position of the infant. This information can be established in several different ways:

Leopold’s maneuvers

Ultrasonography.

• Cervical examination
• Techniques using abdominal palpation Abdominal Palpation Abdominal Examination to determine the presentation of the fetus
• The fetal head will be hard and round.
• The lower body will be bulkier, nodular, and mobile.
• The back will be hard and smooth.
• The other side (anterior surface of the fetus) will be filled with irregular, mobile fetal parts.
• Experienced providers can also estimate the fetal weight using these maneuvers.
• Bedside abdominal ultrasonography can easily identify the fetal head and its orientation Orientation Awareness of oneself in relation to time, place and person. Psychiatric Assessment .
• Quick bedside ultrasonography Bedside Ultrasonography ACES and RUSH: Resuscitation Ultrasound Protocols on admission to labor and delivery to assess fetal presentation is considered standard of care Standard of care The minimum acceptable patient care, based on statutes, court decisions, policies, or professional guidelines. Malpractice .
• The fetal head will typically encompass the entire window and appear like a large white circle (the fetal skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull: Anatomy ).
• Identification Identification Defense Mechanisms of the eyes can help determine position.
• It is quick and easy to perform and presents minimal risk to mother and infant.
• Allowing mothers to labor with infants in a noncephalic presentation significantly increases the risks to both of them.

Suprapubic bedside ultrasound showing the large white circle of the fetal skull, confirming a cephalic presentation F: fetal falx

Vaginal and cervical examination

• As the cervix Cervix The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Externally, the cervix is lined by stratified squamous cells; however, the cervical canal is lined by columnar epithelium. Uterus, Cervix, and Fallopian Tubes: Anatomy dilates, the fetal fontanelles Fontanelles Physical Examination of the Newborn can be directly palpated.
• Identifying the location of the fetal fontanelles Fontanelles Physical Examination of the Newborn allows the practitioner to establish the position.
• Insert 1–2 fingers through the cervix Cervix The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Externally, the cervix is lined by stratified squamous cells; however, the cervical canal is lined by columnar epithelium. Uterus, Cervix, and Fallopian Tubes: Anatomy posteriorly.
• Sweep fingers along the fetal head moving anteriorly.
• This maneuver allows for identification Identification Defense Mechanisms of the sagittal Sagittal Computed Tomography (CT) suture.
• The fontanelles Fontanelles Physical Examination of the Newborn are then identified by moving along the sagittal Sagittal Computed Tomography (CT) suture.

Vertex presentations

• Expectant management
• All have high chances of successful vaginal delivery.

Compound presentations

• Observation when labor is progressing normally (many compound presentations will resolve spontaneously intrapartum).
• Can attempt to gently pinch the compound extremity trying to provoke the fetus into withdrawing the part (no good quality Quality Activities and programs intended to assure or improve the quality of care in either a defined medical setting or a program. The concept includes the assessment or evaluation of the quality of care; identification of problems or shortcomings in the delivery of care; designing activities to overcome these deficiencies; and follow-up monitoring to ensure effectiveness of corrective steps. Quality Measurement and Improvement evidence, but unlikely to be harmful)
• Can attempt to manually replace the compound extremity
• If labor is prolonged and the compound part remains, cesarean delivery Cesarean Delivery Cesarean delivery (CD) is the operative delivery of ≥ 1 infants through a surgical incision in the maternal abdomen and uterus. Cesarean deliveries may be indicated for a number of either maternal or fetal reasons, most commonly including fetal intolerance to labor, arrest of labor, a history of prior uterine surgery, fetal malpresentation, and placental abnormalities. Cesarean Delivery (CD) should be performed.
• Prolonged labor
• Umbilical cord Umbilical cord The flexible rope-like structure that connects a developing fetus to the placenta in mammals. The cord contains blood vessels which carry oxygen and nutrients from the mother to the fetus and waste products away from the fetus. Placenta, Umbilical Cord, and Amniotic Cavity prolapse
• Increased maternal morbidity Morbidity The proportion of patients with a particular disease during a given year per given unit of population. Measures of Health Status from lacerations
• Ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage of the compound part

Brow presentations

• The majority spontaneously convert to a vertex presentation.
• Cesarean delivery Cesarean Delivery Cesarean delivery (CD) is the operative delivery of ≥ 1 infants through a surgical incision in the maternal abdomen and uterus. Cesarean deliveries may be indicated for a number of either maternal or fetal reasons, most commonly including fetal intolerance to labor, arrest of labor, a history of prior uterine surgery, fetal malpresentation, and placental abnormalities. Cesarean Delivery may be required if labor is prolonged.

Face presentations

• Management depends on the position.
• Can be delivered vaginally by an experienced provider
• Cesarean delivery Cesarean Delivery Cesarean delivery (CD) is the operative delivery of ≥ 1 infants through a surgical incision in the maternal abdomen and uterus. Cesarean deliveries may be indicated for a number of either maternal or fetal reasons, most commonly including fetal intolerance to labor, arrest of labor, a history of prior uterine surgery, fetal malpresentation, and placental abnormalities. Cesarean Delivery may be required.
• Head is fully extended and unable to pass through the birth canal Birth canal Pelvis: Anatomy .
• Normally, the fetal head flexes as it passes under the pubic bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types ; however, this is impossible in an MP position.
• Cesarean delivery Cesarean Delivery Cesarean delivery (CD) is the operative delivery of ≥ 1 infants through a surgical incision in the maternal abdomen and uterus. Cesarean deliveries may be indicated for a number of either maternal or fetal reasons, most commonly including fetal intolerance to labor, arrest of labor, a history of prior uterine surgery, fetal malpresentation, and placental abnormalities. Cesarean Delivery is always required (unless the infant spontaneously rotates to a mentum anterior (MA) position).

There are 3 primary options for managing breech presentations: performing CD, attempting an external cephalic version to manually rotate the baby into a vertex presentation for attempted vaginal delivery, or a planned vaginal breech delivery (which is generally not done in the United States).

Natural history of breech presentations

Most infants will spontaneously rotate to a vertex presentation as the pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care progresses. At different gestational ages, the prevalence Prevalence The total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time. Measures of Disease Frequency of breech presentations is:

• < 28 weeks: 20%–25%
• 32 weeks: 10%–15%
• Term (> 37 weeks): 3% 
• Spontaneous version is possible even at > 40 weeks.
• Flexed fetal legs
• Polyhydramnios Polyhydramnios Polyhydramnios is a pathological excess of amniotic fluid. Common causes of polyhydramnios include fetal anomalies, gestational diabetes, multiple gestations, and congenital infections. Patients are often asymptomatic but may present with dyspnea, extremity swelling, or abdominal distention. Polyhydramnios
• Longer umbilical cord Umbilical cord The flexible rope-like structure that connects a developing fetus to the placenta in mammals. The cord contains blood vessels which carry oxygen and nutrients from the mother to the fetus and waste products away from the fetus. Placenta, Umbilical Cord, and Amniotic Cavity
• Lack of fetal/uterine anomalies
• Multiparity

Fetal risks associated with breech presentations

The following risks are associated with breech presentations in utero, regardless of mode of delivery:

• ↑ Association with congenital Congenital Chorioretinitis malformations
• Torticollis Torticollis A symptom, not a disease, of a twisted neck. In most instances, the head is tipped toward one side and the chin rotated toward the other. The involuntary muscle contractions in the neck region of patients with torticollis can be due to congenital defects, trauma, inflammation, tumors, and neurological or other factors. Cranial Nerve Palsies
• Developmental hip dysplasia 

Fetal risks associated with vaginal breech delivery

The primary risk of a vaginal breech delivery is fetal head entrapment:

• The fetal body delivers, but the head remains trapped in the uterus Uterus The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The uterus has a thick wall made of smooth muscle (the myometrium) and an inner mucosal layer (the endometrium). The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Uterus, Cervix, and Fallopian Tubes: Anatomy .
• Causes compression Compression Blunt Chest Trauma of the umbilical cord Umbilical cord The flexible rope-like structure that connects a developing fetus to the placenta in mammals. The cord contains blood vessels which carry oxygen and nutrients from the mother to the fetus and waste products away from the fetus. Placenta, Umbilical Cord, and Amniotic Cavity running past the head (between the delivered umbilicus and the undelivered placenta Placenta A highly vascularized mammalian fetal-maternal organ and major site of transport of oxygen, nutrients, and fetal waste products. It includes a fetal portion (chorionic villi) derived from trophoblasts and a maternal portion (decidua) derived from the uterine endometrium. The placenta produces an array of steroid, protein and peptide hormones (placental hormones). Placenta, Umbilical Cord, and Amniotic Cavity ) 
• Leads to hypoxia Hypoxia Sub-optimal oxygen levels in the ambient air of living organisms. Ischemic Cell Damage until head is delivered → ↑ risk of fetal death
• The cervix Cervix The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Externally, the cervix is lined by stratified squamous cells; however, the cervical canal is lined by columnar epithelium. Uterus, Cervix, and Fallopian Tubes: Anatomy may not be fully dilated enough to accommodate the head.
• The fetal head may not fit through the bony pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy .
• The mother’s expulsive efforts are unable to quickly deliver the head.
• Umbilical cord Umbilical cord The flexible rope-like structure that connects a developing fetus to the placenta in mammals. The cord contains blood vessels which carry oxygen and nutrients from the mother to the fetus and waste products away from the fetus. Placenta, Umbilical Cord, and Amniotic Cavity prolapse during labor → requires emergent CD
• Birth injuries to the fetus (e.g., brachial plexus Brachial Plexus The large network of nerve fibers which distributes the innervation of the upper extremity. The brachial plexus extends from the neck into the axilla. In humans, the nerves of the plexus usually originate from the lower cervical and the first thoracic spinal cord segments (c5-c8 and T1), but variations are not uncommon. Peripheral Nerve Injuries in the Cervicothoracic Region injury)

Vaginal breech delivery

Vaginal breech deliveries for singleton gestations may be considered for certain low-risk women if vaginal delivery is strongly desired by the mother. In contrast, vaginal breech deliveries are done frequently for breech 2nd twins; the procedure is known as a breech extraction.

• Mothers must be fully counseled on risks.
• Mothers and infants should be monitored throughout labor with continuous electronic fetal heart rate Heart rate The number of times the heart ventricles contract per unit of time, usually per minute. Cardiac Physiology (FHR) and tocometry monitors.
• Mothers should understand that a CD will be recommended if there are signs of fetal distress or prolonged labor.
• Avoid artificial rupture of membranes to ↓ risk of cord prolapse.
• Frank or complete breech presentation with no hyperextension of the fetal head on ultrasonography
• No contraindications Contraindications A condition or factor associated with a recipient that makes the use of a drug, procedure, or physical agent improper or inadvisable. Contraindications may be absolute (life threatening) or relative (higher risk of complications in which benefits may outweigh risks). Noninvasive Ventilation to a vaginal birth
• No prior CDs
• Prior successful vaginal deliveries (i.e., multiparity)
• Gestational age Gestational age The age of the conceptus, beginning from the time of fertilization. In clinical obstetrics, the gestational age is often estimated as the time from the last day of the last menstruation which is about 2 weeks before ovulation and fertilization. Pregnancy: Diagnosis, Physiology, and Care ≥ 36 weeks
• Spontaneous labor
• Normal bony pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy shown on X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests
• Estimated fetal weight Estimated Fetal Weight Obstetric Imaging between approximately 2500 and 3500 grams (exact range varies based on clinician Clinician A physician, nurse practitioner, physician assistant, or another health professional who is directly involved in patient care and has a professional relationship with patients. Clinician–Patient Relationship )
• Immediately after delivery of the 1st twin in the cephalic presentation, the physician reaches up into the uterus Uterus The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The uterus has a thick wall made of smooth muscle (the myometrium) and an inner mucosal layer (the endometrium). The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Uterus, Cervix, and Fallopian Tubes: Anatomy , manually grabs the infant’s legs, and gently guides them down through the birth canal Birth canal Pelvis: Anatomy while the cervix Cervix The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Externally, the cervix is lined by stratified squamous cells; however, the cervical canal is lined by columnar epithelium. Uterus, Cervix, and Fallopian Tubes: Anatomy is still fully dilated.
• ↓ Risk of head entrapment compared to singleton vaginal breech deliveries

External cephalic version

An external cephalic version (ECV) is a procedure in which the physician attempts to manually rotate the fetus from a breech to a cephalic presentation by pushing on the maternal abdomen.

• Approximately 50%–60% (higher in multiparous Multiparous A woman with prior deliveries Normal and Abnormal Labor than in nulliparous women) 
• 97% of infants remained cephalic at birth.
• 86% delivered vaginally.
• Women who are candidates for ECV should be counseled on their options to attempt an ECV, or they may simply elect to schedule a CD.
• Infant is full term in case emergent CD is required because of complications from the procedure (e.g., placental abruption Placental Abruption Premature separation of the normally implanted placenta from the uterus. Signs of varying degree of severity include uterine bleeding, uterine muscle hypertonia, and fetal distress or fetal death. Antepartum Hemorrhage ).
• Better ratio of infant size to fluid level than later in pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care
• Allows infant more time for spontaneous version than if the procedure was done earlier
• After a successful version, the mother can await spontaneous labor or be induced immediately, depending on the situation.
• There is still a chance that the infant may spontaneously rotate between the failed ECV and the planned CD date; therefore, presentation should always be checked immediately prior to CD.
• Another contraindication for a vaginal delivery (e.g., placenta previa Placenta Previa Abnormal placentation in which the placenta implants in the lower segment of the uterus (the zone of dilation) and may cover part or all of the opening of the cervix. It is often associated with serious antepartum bleeding and premature labor. Placental Abnormalities )
• Severe oligohydramnios Oligohydramnios Oligohydramnios refers to amniotic fluid volume less than expected for the current gestational age. Oligohydramnios is diagnosed by ultrasound and defined as an amniotic fluid index (AFI) of ‰¤ 5 cm or a single deep pocket (SDP) of Oligohydramnios
• Nonreassuring fetal monitoring Fetal monitoring The primary goals of antepartum testing and monitoring are to assess fetal well-being, identify treatable situations that may cause complications, and evaluate for chromosomal abnormalities. These tests are divided into screening tests (which include cell-free DNA testing, serum analyte testing, and nuchal translucency measurements), and diagnostic tests, which provide a definitive diagnosis of aneuploidy and include chorionic villus sampling (CVS) and amniocentesis. Antepartum Testing and Monitoring prior to the procedure
• A hyperextended fetal head
• Significant fetal or uterine anomalies
• Leads to fetal and maternal hemorrhage
• An immediate CD is required.
• If the version was successful, labor should be induced immediately.
• If the version was unsuccessful, the mother should undergo immediate CD.
• Cord prolapse: can occur with PROM PROM Prelabor rupture of membranes (PROM), previously known as premature rupture of membranes, refers to the rupture of the amniotic sac before the onset of labor. Prelabor rupture of membranes may occur in term or preterm pregnancies. Prelabor Rupture of Membranes and requires immediate/emergent CD.
• Common during the procedure, but typically resolves shortly after pressure on the abdomen is released.
• If distress persists, the mother should undergo an immediate CD.

Cesarean delivery Cesarean Delivery Cesarean delivery (CD) is the operative delivery of ≥ 1 infants through a surgical incision in the maternal abdomen and uterus. Cesarean deliveries may be indicated for a number of either maternal or fetal reasons, most commonly including fetal intolerance to labor, arrest of labor, a history of prior uterine surgery, fetal malpresentation, and placental abnormalities. Cesarean Delivery

• Scheduled at 39 weeks’ gestational age Gestational age The age of the conceptus, beginning from the time of fertilization. In clinical obstetrics, the gestational age is often estimated as the time from the last day of the last menstruation which is about 2 weeks before ovulation and fertilization. Pregnancy: Diagnosis, Physiology, and Care (WGA) if the infant is known to be in the breech presentation.
• Alternative option to attempting ECV
• Postpartum hemorrhage Postpartum hemorrhage Postpartum hemorrhage is one of the most common and deadly obstetric complications. Since 2017, postpartum hemorrhage has been defined as blood loss greater than 1,000 mL for both cesarean and vaginal deliveries, or excessive blood loss with signs of hemodynamic instability. Postpartum Hemorrhage
• Postpartum endomyometritis
• Maternal injury
• Longer recovery time postpartum
• Complications in future pregnancies (e.g., placenta previa Placenta Previa Abnormal placentation in which the placenta implants in the lower segment of the uterus (the zone of dilation) and may cover part or all of the opening of the cervix. It is often associated with serious antepartum bleeding and premature labor. Placental Abnormalities , placenta accreta Placenta Accreta Abnormal placentation in which all or parts of the placenta are attached directly to the myometrium due to a complete or partial absence of decidua. It is associated with postpartum hemorrhage because of the failure of placental separation. Placental Abnormalities , uterine rupture Uterine Rupture A complete separation or tear in the wall of the uterus with or without expulsion of the fetus. It may be due to injuries, multiple pregnancies, large fetus, previous scarring, or obstruction. Antepartum Hemorrhage )
• Maternal request (mother declines ECV attempt)
• ECV contraindicated
• ECV unsuccessful
• Fetal distress during labor

Management of transverse presentations

• As with breech presentations, mothers may be offered an attempt at ECV or a CD.
• Unlike breech presentations, vaginal transverse delivery is always contraindicated.
• Hofmeyr, G.J. (2021). Overview of breech presentation. In Barss, V.A. (Ed.), UpToDate. Retrieved July 14, 2021, from https://www.uptodate.com/contents/overview-of-breech-presentation  
• Hofmeyr, G.J. (2021). Delivery of the singleton fetus in breech presentation. In Barss, V.A. (Ed.), UpToDate. Retrieved July 14, 2021, from https://www.uptodate.com/contents/delivery-of-the-singleton-fetus-in-breech-presentation  
• Hofmeyr, G.J. (2021). External cephalic version. In Barss, V.A. (Ed.), UpToDate. Retrieved July 14, 2021, from https://www.uptodate.com/contents/external-cephalic-version  
• Julien, S., and Galerneau, F. (2021). Face and brow presentations in labor. In Barss, V.A., (Ed.), UpToDate. Retrieved July 14, 2021, from https://www.uptodate.com/contents/face-and-brow-presentations-in-labor  
• Strauss, R.A., Herrera, C.A. (2021). Transverse fetal lie. In Barss, V.A., (Ed.), UpToDate. Retrieved July 14, 2021, from https://www.uptodate.com/contents/transverse-fetal-lie  
• Barth, W.H. (2021). Compound fetal presentation. In Barss, V.A., (Ed.), UpToDate. Retrieved July 14, 2021, from https://www.uptodate.com/contents/compound-fetal-presentation  
• Cunningham, F. G., Leveno, K. J., et al. (2010). Williams Obstetrics, 23rd ed., pp. 374‒382. 

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vertex presentation

Medical Definition of vertex presentation

Dictionary entries near vertex presentation, cite this entry.

“Vertex presentation.” Merriam-Webster.com Medical Dictionary , Merriam-Webster, https://www.merriam-webster.com/medical/vertex%20presentation. Accessed 10 Apr. 2024.

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Google highlighted new Vertex AI tools available to Google Cloud's enterprise customers as well that can support their integration of AI.

Google said the Vertex AI Agent Builder can help developers build and deploy generative AI agents using Google’s latest Gemini models.

Alphabet shares climbed 1.1% Tuesday to close at a record high of $156.60. The stock has gained over 13% year to date and more than 47% over the past 12 months.

UPDATE—April 9, 2024: This article has been updated to reflect a title change and more recent share price information.

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On the business, strategy, and impact of technology.

Gemini 1.5 and Google’s Nature

It was impossible to miss the leading message at yesterday’s Google Cloud Next keynote : Google has the best infrastructure for AI. This was CEO Sundar Pichai in his video greeting:

I want to highlight just a few reasons Google Cloud is showing so much progress. One is our deep investments in AI. We’ve known for a while that AI would transform every industry and company, including our own. That’s why we’ve been building AI infrastructure for over a decade, including TPUs, now in their 5th generation. These advancements have helped customer train and serve cutting-edge language models. These investments put us in the forefront of the AI platform shift.

Google Cloud CEO Thomas Kurian made the priority clear as well:

Today we’re going to focus on how Google is helping leading companies transform their operations and become digital and AI leaders, which is the new way to cloud. We have many important advances, starting with our infrastructure.

What was most interesting about the keynote, though, is what that infrastructure makes possible, and, by extension, what that says about Google’s ability to compete.

One of the most surprising things about large language models (LLMs) is how much they know; from the very beginning, though, hallucinations have been a concern. Hallucinations are, of course, part of what makes LLMs so impressive: a computer is actually being creative! It’s also a feature that isn’t particularly impressive to the enterprise customers that this keynote was directed at.

To that end, Kurian, shortly after going over Google’s infrastructure advantages, talked about “grounding”, both in terms of the company’s Gemini model broadly, and for enterprise use cases specifically in the context of Google’s Vertex AI model management service:

To augment models, Vertex AI provides managed tooling to connect your model to enterprise applications and databases, using extensions and function-calling. Vertex also provides retrieval augmented generation (RAG) combining the strengths of retrieval and generative models to provide high quality personalized answers and recommendations. Vertex can augment models with up-to-date knowledge from the web and from your organization, combining generative AI with your enterprise truth. Today we have a really important announcement: you can now ground with Google Search, perhaps the world’s most trusted source of factual information, with a deep understanding of the world’s knowledge. Grounding Gemini’s responses with Google Search improves response quality and significantly reduces hallucinations. Second, we’re also making it easy to ground your models with data from your enterprise databases and applications, and any database anywhere. Once you’ve chosen the right model, tuned it, and connected it with your enterprise truth, Vertex’s MLOps can help you manage and monitor models.

A RAG implementation using Google Search is an obvious win, and mirrors ChatGPT’s integration with Bing (or Microsoft Copilot in Bing): the LLM provides answers when it can, and searches the web for things it doesn’t know, a particularly useful feature if you are looking for more recent information.

A more impressive demonstration of grounding, though, was in the context of integrating Gemini with Google’s BigQuery data warehouse and Looker business intelligence platform :

In this demo, the worker gets an alert that a particular product is selling out; using generative AI the worker can see sales trends, find similar models, and create a plan of action for dealing with declining inventory for delivery to her team.

What is notable is not the demo specifics (which is unapologetically made-up for Cymbal, Google’s demo brand ); rather, note the role of the LLM: it is not providing information or taking specific actions, but rather serving as a much more accessible natural language interface to surface and collect data that would otherwise take considerably more expertise and time. In other words, it is trustworthy because it is grounded through integration Google is promising with its other enterprise data services.

At the same time, that last section didn’t really follow on from the introduction: yes, those LLMs leveraging Google or BigQuery are running on Google’s infrastructure, but other companies or startups can build something similar. This is where the rest of Pichai’s introduction comes in:

We also continue to build capable AI models to make products like search, Maps, and Android radically more helpful. In December, we took our next big step with Gemini, our largest and most capable model yet. We’ve been bringing it to our products and to enterprises and developers through our APIs. We’ve already introduced our next generation Gemini 1.5 Pro. It’s been in private preview in Vertex AI. 1.5 Pro shows dramatically enhanced performance and includes a breakthrough in long context understanding. That means it can run 1 million tokens of information consistently, opening up new possibilities for enterprises to create, discover, and build using AI. There’s also Gemini’s multi-modal capabilities, which can process audio, video, text, code and more. With these two advances, enterprises can do things today that just weren’t possible with AI before.

Google hasn’t said how Gemini 1.5 was made, but clearly the company has overcome the key limitation of traditional transformers: memory requirements increase quadratically with context length. One promising approach is Ring Attention with Blockwise Transformers , which breaks long contexts into pieces to be computed individually even as the various devices computing those pieces simultaneously communicate to make sense of the context as a whole; in this case memory requirements scale linearly with context length, and can be extended by simply adding more devices to the ring topology.

This is where Google’s infrastructure comes in: the company not only has a massive fleet of TPUs, but has also been developing those TPUs to run in parallel at every level of the stack, from chip to cluster to even data centers (this latter requirement is more pertinent for training than inference); if there is a solution that calls for scale, Google is the best placed to provide it, and it seems the company has done just that with Gemini 1.5.

To that end, and per Pichai’s closing line, almost all of the other demos in the keynote were implicitly leveraging Gemini 1.5’s context window.

In a Gemini for Workspaces demo, the worker evaluated two statements of work against each other, and against the company’s compliance document:

Here are the key quotes:

Google Drive is ready without any additional AI pre-work… Each of these documents is over 70 pages. It would have taken me hours to review these docs, but instead Gemini is going to help me find a clean answer to save me a ton of time… Before I proceed with this vendor, I need to ensure that no compliance issues exist, and I’m going to be honest, I have not memorized every rule in our compliance rulebook because it is over 100 pages. I would have to need to scour the 80 pages of this proposal and compare it manually with the 100 pages of the rulebook. So instead, in the side panel I ask, “Does this offer comply with the following” and I’m going to just @-mention our compliance rulebook, hit Enter, and see what Gemini has to say. So interesting: Gemini has found an issue, because the supplier has not listed their security certifications. Because Gemini is grounded in my company’s data, with source citations to specific files, I can trust this response and start to troubleshoot before selecting a vendor.

The key distinction between this demo and the last one is that quote at the beginning: a large context window just works in a far greater number of use cases, without any fiddly RAG implementations or special connections to external data stores; just upload the files you need to analyze, and you’re off.

In a Creative Agent with Imagen demo, the worker was seeking to create marketing images and storyboards for an outdoor product:

Here is the key quote:

The creative agent can analyze our previous campaigns to understand our unique brand style and apply it to new ideas. In this case, the creative agent has analyzed over 3,000 brand images, descriptions, videos, and documents of other products that we have in our catalog, contained within Google Drive, to create this summary…The creative agent was able to use Gemini Pro’s 1 million token context window and it’s ability to reason across text, images, and video to generate this summary.

This was, to be fair, one of the weaker demos: the brand summary and marketing campaign weren’t that impressive, and the idea of creating a podcast with synthetic voices is technically impressive and also something that will never be listened to. That, though, is impressive in its own right: as I noted in an Update when Gemini 1.5 was first announced , “a massively larger context window makes it possible to do silly stuff”, and silly stuff often turns into serious capabilities.

In a Gemini Code Assistant Demo (formerly Duet AI for Developers), a developer new to a job (and the codebase) was tasked with making a change to a site’s homepage:

For the developers out there, you know that this means we’re going to need to add padding in the homepage, modify some views, make sure the configs are changed for our microservices, and typically, it would take me a week or two to even just get familiarized with our company’s code base which has over 100,000 lines of code over 11 services. But now, with Gemini Code Assist, as a new engineer on the team, I can be more productive than ever and can accomplish all of this work in just a matter of minutes. This is because Gemini’s code transformations with full codebase awareness allows us to easily reason through our entire codebase, and in comparison, other models out there can’t handle anything beyond 12,000 to 15,000 lines of code. Gemini with Code Assist is so intelligent that we can just give it our business requirements, including the visual design…Gemini Code Assist doesn’t just suggest code edits; it provides clear recommendations, and makes sure that all of these recommendations align with [the company’s] security and compliance requirements…

And the conclusion:

Let’s recap: behind the scenes Gemini has analyzed my entire codebase in GitLab; it has implemented a new feature; and has ensured that all of the code generated is compatible with my company’s standards and requirements.

Again, leave aside the implausibility of this demo: the key takeaway is the capabilities unlocked when the model is able to have all of the context around a problem while working; this is only possible with — and here the name is appropriate — a long context window, and that is ultimately enabled by Google’s infrastructure.

Google’s Nature

In case it isn’t clear, I think that this keynote was by far the most impressive presentation Google has made in the AI era, not least because the company knows exactly what its advantages are. Several years ago I wrote an Article called Microsoft’s Monopoly Hangover that discussed the company’s then-ongoing transition away from Windows as the center of its strategy; the central conceit was a comparison to Lou Gerstner’s 1990’s transformation of IBM.

The great thing about a monopoly is that a company can do anything, because there is no competition; the bad thing is that when the monopoly is finished the company is still capable of doing anything at a mediocre level, but nothing at a high one because it has become fat and lazy. To put it another way, for a former monopoly “big” is the only truly differentiated asset.

My argument was that business models could be changed: IBM did it, and Microsoft was in the process of doing so when I wrote that. Moreover, Gerstner had shown that culture could be changed as well, and Nadella did just that at Microsoft . What couldn’t be changed was nature: IBM was a company predicated on breadth, not specialization; that’s why Gerstner was right to not break apart the company but to instead deliver Internet solutions to enterprises. Similarly, Microsoft was a company predicated on integration around Windows; the company’s shift to services centered on Teams as Microsoft’s operating system in the cloud was also true to the company’s nature.

Google is facing many of the same challenges after its decades long dominance of the open web: all of the products shown yesterday rely on a different business model than advertising, and to properly execute and deliver on them will require a cultural shift to supporting customers instead of tolerating them. What hasn’t changed — because it is the company’s nature, and thus cannot — is the reliance on scale and an overwhelming infrastructure advantage. That, more than anything, is what defines Google, and it was encouraging to see that so explicitly put forward as an advantage.

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Google Cloud Next 2024: Everything announced so far

Google’s Cloud Next 2024 event takes place in Las Vegas through Thursday, and that means lots of new cloud-focused news on everything from Gemini, Google’s AI-powered chatbot , to AI to devops and security. Last year’s event was the first in-person Cloud Next since 2019, and Google took to the stage to show off its ongoing dedication to AI with its Duet AI for Gmail and many other debuts , expansion of generative AI to its security product line in addition to other enterprise-focused updates and debuts .

Don’t have time to watch the full archive of Google’s keynote event ? That’s OK; we’ve summed up the most important parts of the event below, with additional details from the TechCrunch team on the ground at the event. And that Tuesday’s updates aren’t the only things Google is making available to non-attendees, Wednesday’s developer-focused stream begins at 10:30 a.m. PT right here .

Google Vids

Leveraging AI to help customers develop creative content is something Big Tech is looking for, and Tuesday, Google introduced its version. Google Vids, a new AI-fueled video creation tool , is the latest feature added to the Google Workspace.

Here’s how it works: Google claims users can make videos alongside other Workspace tools like Docs and Sheets. The editing, writing and production is all there. You can also collaborate with colleagues in real time within Google Vids. Read more

Gemini Code Assist

After reading about Google’s new Gemini Code Assist , an enterprise-focused AI code completion and assistance tool, you may be asking yourself if that sounds familiar. And you would be correct. TechCrunch Senior Editor Frederic Lardinois writes that “Google previously offered a similar service under the now-defunct Duet AI branding.” Then Gemini came along. Code Assist is a direct competitor to GitHub’s Copilot Enterprise. Here’s why

Google Workspace

Among the new features are voice prompts to kick off the AI-based “Help me write” feature in Gmail while on the go . Another one for Gmail includes a way to instantly turn rough email drafts into a more polished email. Over on Sheets, you can send out a customizable alert when a certain field changes. Meanwhile, a new set of templates make starting a new spreadsheet easier. For the Doc lovers, there is support for tabs now. This is good because, according to the company, you can “organize information in a single document instead of linking to multiple documents or searching through Drive.” Of course, subscribers get the goodies first. Read more

Google also seems to have plans to monetize two of its new AI features for the Google Workspace productivity suite. This will look like $10/month/user add-on packages. One will be for the new AI meetings and messaging add-on that takes notes for you, provides meeting summaries and translates content into 69 languages. The other is for the introduced AI security package, which helps admins keep Google Workspace content more secure. Read more

In February, Google announced an image generator built into Gemini, Google’s AI-powered chatbot. The company pulled it shortly after it was found to be randomly injecting gender and racial diversity into prompts about people. This resulted in some offensive inaccuracies. While we waited for an eventual re-release, Google came out with the enhanced image-generating tool, Imagen 2 . This is inside its Vertex AI developer platform and has more of a focus on enterprise. Imagen 2 is now generally available and comes with some fun new capabilities, including inpainting and outpainting. There’s also Google’s calling “text-to-live images” where you  can now create short, four-second videos from text prompts, along the lines of AI-powered clip generation tools like Runway ,  Pika  and  Irreverent Labs . Read more

Vertex AI Agent Builder

We can all use a little bit of help, right? Meet Google’s Vertex AI Agent Builder, a new tool to help companies build AI agents.

“Vertex AI Agent Builder allows people to very easily and quickly build conversational agents,” Google Cloud CEO Thomas Kurian said. “You can build and deploy production-ready, generative AI-powered conversational agents and instruct and guide them the same way that you do humans to improve the quality and correctness of answers from models.”

To do this, the company uses a process called “grounding,” where the answers are tied to something considered to be a reliable source. In this case, it’s relying on Google Search (which in reality could or could not be accurate). Read more

Gemini comes to databases

Google calls Gemini in Databases a collection of features that “simplify all aspects of the database journey.” In less jargony language, it’s a bundle of AI-powered, developer-focused tools for Google Cloud customers who are creating, monitoring and migrating app databases. Read more

Google renews its focus on data sovereignty

Image Credits: MirageC / Getty Images

Google has offered cloud sovereignties before, but now it is focused more on partnerships rather than building them out on their own. Read more

Security tools get some AI love

Google jumps on board the productizing generative AI-powered security tool train with a number of new products and features aimed at large companies. Those include Threat Intelligence, which can analyze large portions of potentially malicious code. It also lets users perform natural language searches for ongoing threats or indicators of compromise. Another is Chronicle, Google’s cybersecurity telemetry offering for cloud customers to assist with cybersecurity investigations. The third is the enterprise cybersecurity and risk management suite Security Command Center. Read more

Nvidia’s Blackwell platform

One of the anticipated announcements is Nvidia’s next-generation Blackwell platform coming to Google Cloud in early 2025. Yes, that seems so far away. However, here is what to look forward to: support for the high-performance Nvidia HGX B200 for AI and HPC workloads and GB200 NBL72 for large language model (LLM) training. Oh, and we can reveal that the GB200 servers will be liquid-cooled. Read more

Chrome Enterprise Premium

Meanwhile, Google is expanding its Chrome Enterprise product suite with the launch of Chrome Enterprise Premium . What’s new here is that it mainly pertains to mostly to security capabilities of the existing service, based on the insight that browsers are now the endpoints where most of the high-value work inside a company is done. Read more

Gemini 1.5 Pro

Image Credits: Google

Open-source tools

At Google Cloud Next 2024, the company debuted a number of open-source tools primarily aimed at supporting generative AI projects and infrastructure. One is Max Diffusion, which is a collection of reference implementations of various diffusion models that run on XLA, or Accelerated Linear Algebra, devices. Then there is Jetstream, a new engine to run generative AI models. The third is MaxTest, a collection of text-generating AI models targeting TPUs and Nvidia GPUs in the cloud. Read more

We don’t know a lot about this one, however, here is what we do know : Google Cloud joins AWS and Azure in announcing its first custom-built Arm processor, dubbed Axion. Frederic Lardinois writes that “based on Arm’s Neoverse 2 designs, Google says its Axion instances offer 30% better performance than other Arm-based instances from competitors like AWS and Microsoft and up to 50% better performance and 60% better energy efficiency than comparable X86-based instances.” Read more

The entire Google Cloud Next keynote

If all of that isn’t enough of an AI and cloud update deluge, you can watch the entire event keynote via the embed below.