uterine presentation in pregnancy

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

• Variations in Fetal Position and Presentation |

During pregnancy, the fetus can be positioned in many different ways inside the mother's uterus. The fetus may be head up or down or facing the mother's back or front. At first, the fetus can move around easily or shift position as the mother moves. Toward the end of the pregnancy the fetus is larger, has less room to move, and stays in one position. How the fetus is positioned has an important effect on delivery and, for certain positions, a cesarean delivery is necessary. There are medical terms that describe precisely how the fetus is positioned, and identifying the fetal position helps doctors to anticipate potential difficulties during labor and delivery.

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 uterus is abnormally shaped or contains growths such as fibroids .

The fetus has a birth defect .

There is more than one fetus (multiple gestation).

Position and Presentation of the Fetus

Variations in Fetal Position and Presentation

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).

When a fetus faces up, the neck is often straightened rather than bent,which requires more room for the head to pass through the birth canal. Delivery assisted by a vacuum device or forceps or cesarean delivery may be necessary.

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.

In a first delivery, these problems may occur more frequently because a woman’s tissues have not been stretched by previous deliveries. Because of risk of injury or even death to the baby, cesarean delivery is preferred when the fetus is in breech presentation, unless the doctor is very experienced with and skilled at delivering breech babies or there is not an adequate facility or equipment to safely perform a cesarean delivery.

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

Labor starts too soon (preterm labor).

The uterus is abnormally shaped or contains abnormal growths such as fibroids .

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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Presentation and position of baby through pregnancy and at birth

9-minute read

If you are concerned about your baby’s movements, contact your doctor or midwife for advice immediately.

• If you baby is in a breech presentation, your doctor may recommend trying a technique called an external cephalic version to try and move your baby while they are still in the uterus for an easier birth.

What does presentation and position mean?

Presentation refers to the part of your baby’s body that is facing downwards in the direction of the birth canal.

Position refers to where your baby’s occiput (the bottom part of the back of their head) is in relation to your body.

If your baby is in a breech presentation , then position refers to where your baby’s sacrum (lower back) is in relation to your body.

People — including medical professionals — sometimes use these terms incorrectly. Sometimes when speaking about babies in breech presentation, the word ‘position’ will be used to refer to their presentation. For example, you may read information or hear people say ‘breech position’ instead of ‘breech presentation’.

What are the different types of presentation my baby could be in during pregnancy and birth?

Most babies present headfirst, also known as cephalic presentation. Most babies that are headfirst will be vertex presentation. This means that the crown of their head sits at the opening of your birth canal.

In rare cases, your baby can be headfirst but in face or brow presentation, which may not be suitable for vaginal birth.

If your baby is in a breech presentation, their feet or bottom will be closest to your birth canal. The 3 most common types of breech presentation are:

• frank or extended breech — where your baby’s legs are straight up in front of their body, with their feet up near their face
• complete or flexed breech — where your baby is in a sitting position with their legs crossed in front of their body and their feet near their bottom
• footling breech — where one or both of your baby’s feet are hanging below their bottom, so the foot or feet are coming first

Read more on breech presentation .

What are the different positions my baby could be in during pregnancy and birth?

If your baby is headfirst, the 3 main types of presentation are:

• anterior – when the back of your baby’s head is at the front of your belly
• lateral – when the back of your baby’s head is facing your side
• posterior – when the back of your baby’s head is towards your back

How will I know what presentation and position my baby is in?

Your doctor or midwife can usually work out your baby’s presentation by feeling your abdomen. They may also double check it with a portable ultrasound. Your baby’s presentation is usually checked around 36 weeks .

Your doctor or midwife will also confirm your baby’s head position in labour by examining your belly and using an ultrasound , and they may also do a vaginal examination . During the vaginal examination they are feeling for certain ridges on your baby’s head called sutures and fontanelles that help them work out which way your baby is positioned.

What is the ideal presentation and position for baby to be in for a vaginal birth?

For a vaginal birth, your baby will ideally be headfirst with the back of their head at the front of your belly, also known as being in the anterior position. This position is best for labour and birth since it means that the smallest part of your baby’s head goes down the birth canal first.

When does a baby usually get in the ideal presentation and position for birth?

Your baby will usually be in a headfirst position by 37 weeks of pregnancy. Around 3 in every 100 babies will be in breech presentation after 37 weeks.

Your baby’s position can change with your contractions during labour as they move down the birth canal, so their exact position can change during labour.

What are my options if baby isn't in the ideal presentation or position for a vaginal birth?

If your baby is in a breech presentation, your doctor may recommend a technique called an external cephalic version (ECV) to try and move your baby while they are still in the uterus . An ECV involves your doctor using their hands to apply pressure on your belly and help turn your baby to a headfirst position. It has a 1 in 2 chance of success and is a safe option in most pregnancies.

There is no evidence to show that alternative therapies, such as exercises, acupuncture or chiropractic treatments, help your baby change from a breech presentation to headfirst.

If your baby remains breech, your doctor may discuss having a breech vaginal birth. Not all doctors and hospitals offer this option. They may also suggest you birth your baby with a planned caesarean section .

If your baby’s presentation is headfirst but the position of your baby’s head is not ideal for labour, it can lead to a longer labour, and potential complications . The position of your baby’s head will often change as your labour progresses. If it doesn’t, sometimes you can still give birth without assistance, or you may need your doctor to help turn your baby’s head or help your birth with a vacuum or forceps .

Any procedure or decision for a type of birth will only go ahead with your consent . You will be able to discuss all the options with your doctor, and based on your preferences for yourself and your baby’s safety, make a decision together .

Resources and support

The Royal Australian and New Zealand College of Obstetrics and Gynaecology has a factsheet about the options available to you if your baby is in a breech presentation at the end of your pregnancy .

Mercy Perinatal has information on external cephalic version (ECV) safety and benefits if your baby is in a breech presentation at the end of your pregnancy.

The Women’s Hospital has information about the different presentations and positions your baby could be in, and how it can affect your birthing experience.

Speak to a maternal child health nurse

Call Pregnancy, Birth and Baby to speak to a maternal child health nurse on 1800 882 436 or video call . Available 7am to midnight (AET), 7 days a week.

Learn more here about the development and quality assurance of healthdirect content .

Last reviewed: October 2023

Related pages

External cephalic version (ecv), malpresentation, breech pregnancy, search our site for.

• Foetal Version
• Breech Presentation

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Top results

Breech presentation and turning the baby

In preparation for a safe birth, your health team will need to turn your baby if it is in a bottom first ‘breech’ position.

Read more on WA Health website

Breech Presentation at the End of your Pregnancy

Breech presentation occurs when your baby is lying bottom first or feet first in the uterus (womb) rather than the usual head first position. In early pregnancy, a breech position is very common.

Read more on RANZCOG - Royal Australian and New Zealand College of Obstetricians and Gynaecologists website

External Cephalic Version for Breech Presentation - Pregnancy and the first five years

This information brochure provides information about an External Cephalic Version (ECV) for breech presentation

Read more on NSW Health website

When a baby is positioned bottom-down late in pregnancy, this is called the breech position. Find out about 3 main types and safe birthing options.

Read more on Pregnancy, Birth & Baby website

Malpresentation is when your baby is in an unusual position as the birth approaches. Sometimes it’s possible to move the baby, but a caesarean maybe safer.

Labour complications

Even if you’re healthy and well prepared for childbirth, there’s always a chance of unexpected problems. Learn more about labour complications.

ECV is a procedure to try to move your baby from a breech position to a head-down position. This is performed by a trained doctor.

Having a baby

The articles in this section relate to having a baby – what to consider before becoming pregnant, pregnancy and birth, and after your baby is born.

Anatomy of pregnancy and birth - pelvis

Your pelvis helps to carry your growing baby and is tailored for vaginal births. Learn more about the structure and function of the female pelvis.

Planned or elective caesarean

There are important things to consider if you are having a planned or elective caesarean such as what happens during and after the procedure.

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Changes During Pregnancy

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Changes During Pregnancy (Text Version)

Month 1 to 2 Weeks 1 to 8 [Image of an embryo in a uterus during the first or second month of pregnancy]

The egg is fertilized by sperm and a growing ball of cells called the blastocyst implants in the uterus.

Week 5 begins the embryo stage of development.

The brain and spine begin to form, followed by the neural tube.

Cardiac tissue starts to develop.

Parts of the face take shape and the inner ear begins to develop.

Arm and leg buds appear, and then webbed fingers and toes emerge.

The long tube that will become the digestive tract takes shape.

By the end of week 8, the embryo is about half an inch long.

Month 3 Weeks 9 to 12 [Image of a fetus in a uterus during the third month of pregnancy]

Cartilage for the limbs, hands, and feet is forming but won’t harden into bones for a few weeks.

Eyelids form but remain closed.

The head develops a rounded shape.

Week 11 begins the fetus stage of development.

The fetus makes breathing-like movements and swallows amniotic fluid.

The kidneys are making urine, the pancreas is making insulin, and fingernails have formed.

By the end of week 12, the fetus is about 2 inches long and weighs about half an ounce.

Month 4 Weeks 13 to 16 [Image of a fetus in a uterus during the fourth month of pregnancy]

By week 13, all major organs have formed and will continue to develop.

Bones are hardening, especially the long bones.

The skin is thin and see-through but will start to thicken soon.

At week 14, the neck is defined, and the lower limbs are developed.

The fetus’s hearing begins to develop.

The lungs begin to form tissue that will allow them to exchange oxygen and carbon dioxide after birth.

Limb movements become more coordinated.

By the end of week 16, the fetus is more than 4 inches long and weighs more than 3 ounces.

Month 5 Weeks 17 to 20 [Image of a fetus in a uterus during the fifth month of pregnancy]

At week 18, the fetus can hear sounds.

The part of the brain that controls motor movements is fully formed.

The digestive system is working.

At week 19, the ears, nose, and lips may be recognizable on an ultrasound exam.

Soft, downy hair called lanugo is starting to form all over the body.

By the end of week 20, the fetus is more than 6 inches long and weighs less than 11 ounces.

Month 6 Weeks 21 to 24 [Image of a fetus in a uterus during the sixth month of pregnancy]

The fetus’s kicks and turns are stronger now.

If the hand floats to the mouth, the fetus may suck its thumb.

Eyebrows are visible.

At week 23, most of the fetus’s sleep time is spent in rapid eye movement (REM) sleep.

Ridges are forming in the hands and feet that later will be fingerprints and footprints.

The lungs continue to develop.

By the end of week 24, the fetus is about 12 inches long and weighs about 1½ pounds.

Month 7 Weeks 25 to 28 [Image of a fetus in a uterus during the seventh month of pregnancy]

The fetus can respond with movement to familiar sounds, such as your voice.

The lungs are now fully formed but not yet ready to function outside the uterus.

Loud sounds may make the fetus respond by pulling in arms and legs.

The lungs begin making surfactant, a substance needed for breathing after birth.

At 27 weeks, more fat is being added to keep the fetus warm.

A greasy material called vernix has started to develop. Vernix acts as a waterproof barrier that protects the skin.

By the end of week 28, the fetus is nearly 15 inches long and weighs about 2½ pounds.

Month 8 Weeks 29 to 32 [Image of a fetus in a uterus during the eighth month of pregnancy]

The fetus can stretch, kick, and make grasping motions.

The eyes can open and close and sense changes in light.

The bone marrow is forming red blood cells.

At week 31, major development is finished, and the fetus is gaining weight very quickly.

In boys, the testicles have begun to descend into the scrotum.

At week 32, the fine hair that covered the fetus's body (lanugo) begins to disappear.

By the end of week 32, the fetus is almost 17 inches long and weighs a little more than 4 pounds.

Month 9 Weeks 33 to 36 [Image of a fetus in a uterus during the ninth month of pregnancy]

The brain is growing and developing rapidly.

The bones harden, but the skull remains soft and flexible.

More fat is forming under the skin.

The fingernails have grown to the ends of the fingers.

During week 36 or 37, most fetuses turn to a head-down position for birth.

By the end of week 36, the fetus is about 18 inches long and weighs a little more than 6 pounds.

Month 10 Weeks 37 to 40 [Image of a fetus in a uterus during the tenth month of pregnancy]

The lungs, brain, and nervous system continue to develop.

The circulatory system is complete, and so is the musculoskeletal system.

The fetus is taking up a lot of space in the amniotic sac and you should continue to feel movement.

By now, the fetus’s head may have dropped lower into position in your pelvis.

By the end of week 40, the fetus is 20 inches long and may weigh 7½ to 8 pounds.

How the Uterus Grows During Pregnancy

The size of your uterus can help show how long you have been pregnant. The uterus fits inside the pelvis until week 12. By week 36, the top of the uterus is under your rib cage.

[A pregnant woman is shown with dotted lines on her abdomen to mark how the uterus grows during pregnancy. Each line marks four weeks of pregnancy, from week 12 to week 40. The lines move from the bottom of her abdomen to the top of her abdomen.]

Changes In Your Body

The First Trimester

Your period stops.

Your breasts may become larger and more tender.

Your nipples may stick out more.

You may need to urinate more often.

You may feel very tired.

You may feel nauseated and may vomit.

You may crave certain foods or lose your appetite.

You may have heartburn or indigestion.

You may feel bloated and have excess gas.

You may be constipated.

You may gain or lose a few pounds.

The Second Trimester

Your appetite increases and nausea and fatigue may ease.

Your abdomen begins to expand. By the end of this trimester, the top of your uterus will be near your rib cage.

You will begin to feel the fetus move.

The skin on your abdomen stretches and may feel tight and itchy. You may see stretch marks.

Your abdomen may ache on one side or the other as the ligaments that support your uterus are stretched.

You may get brown patches, called the “mask of pregnancy,” on your face.

Your areolas, the darker skin around your nipples, may darken.

Your feet and ankles may swell.

The Third Trimester

You can feel the fetus's movements strongly.

You may be short of breath.

You may need to urinate more often as the fetus drops and puts extra pressure on your bladder.

Colostrum—a yellow, watery premilk—may leak from your nipples.

Your navel may stick out.

You may have contractions (abdominal tightening or pain). These can signal false or real labor.

PFSI026: This information is designed as an educational aid to patients and sets forth current information and opinions related to women’s health. It is not intended as a statement of the standard of care, nor does it comprise all proper treatments or methods of care. It is not a substitute for a treating clinician’s independent professional judgment. For ACOG’s complete disclaimer, visit www.acog.org/WomensHealth-Disclaimer .

Copyright November 2023 by the American College of Obstetricians and Gynecologists. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, posted on the internet, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher.

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Section 24: Development and Pregnancy

Gestational parent changes during pregnancy, labor, and birth, learning objectives.

By the end of this section, you will be able to:

• Explain how estrogen, progesterone, and hCG are involved in maintaining pregnancy
• List the contributors to weight gain during pregnancy
• Describe the major changes to the gestational parent’s digestive, circulatory, and integumentary systems during pregnancy
• Summarize the events leading to labor
• Identify and describe each of the three stages of childbirth

A full-term pregnancy lasts approximately 270 days (approximately 38.5 weeks) from conception to birth. Because it is easier to remember the first day of the last menstrual period (LMP) than to estimate the date of conception, obstetricians set the due date as 284 days (approximately 40.5 weeks) from the LMP. This assumes that conception occurred on day 14 of the ovarian cycle, which is usually a good approximation. The 40 weeks of an average pregnancy are usually discussed in terms of three trimesters , each approximately 13 weeks. During the second and third trimesters, the pre-pregnancy uterus—about the size of a fist—grows dramatically to contain the fetus, causing a number of anatomical changes in the parent.

Figure 1. The uterus grows throughout pregnancy to accommodate the fetus.

Effects of Hormones

Virtually all of the effects of pregnancy can be attributed in some way to the influence of hormones—particularly estrogens, progesterone, and hCG. During weeks 7–12 from the LMP, the pregnancy hormones are primarily generated by the corpus luteum. Progesterone secreted by the corpus luteum stimulates the production of decidual cells of the endometrium that nourish the blastocyst before placentation. As the placenta develops and the corpus luteum degenerates during weeks 12–17, the placenta gradually takes over as the endocrine organ of pregnancy.

The placenta converts weak androgens secreted by the parental and fetal adrenal glands to estrogens, which are necessary for pregnancy to progress. Estrogen levels climb throughout the pregnancy, increasing 30-fold by childbirth. Estrogens have the following actions:

• They suppress FSH and LH production, effectively preventing ovulation. (This function is the biological basis of hormonal birth control pills.)
• They induce the growth of fetal tissues and are necessary for the maturation of the fetal lungs and liver.
• They promote fetal viability by regulating progesterone production and triggering fetal synthesis of cortisol, which helps with the maturation of the lungs, liver, and endocrine organs such as the thyroid gland and adrenal gland.
• They stimulate tissue growth in the gestational parent, leading to uterine enlargement and mammary duct expansion and branching.

Relaxin, another hormone secreted by the corpus luteum and then by the placenta, helps prepare the gestational parent’s body for childbirth. It increases the elasticity of the symphysis pubis joint and pelvic ligaments, making room for the growing fetus and allowing expansion of the pelvic outlet for childbirth. Relaxin also helps dilate the cervix during labor.

The placenta takes over the synthesis and secretion of progesterone throughout pregnancy as the corpus luteum degenerates. Like estrogen, progesterone suppresses FSH and LH. It also inhibits uterine contractions, protecting the fetus from preterm birth. This hormone decreases in late gestation, allowing uterine contractions to intensify and eventually progress to true labor. The placenta also produces hCG. In addition to promoting survival of the corpus luteum, hCG stimulates fetal sperm producing organs to secrete testosterone, which is essential for the development of the sperm producing and conducting organs.

The anterior pituitary enlarges and ramps up its hormone production during pregnancy, raising the levels of thyrotropin, prolactin, and adrenocorticotropic hormone (ACTH). Thyrotropin, in conjunction with placental hormones, increases the production of thyroid hormone, which raises the parental metabolic rate. This can markedly augment a pregnant individual’s appetite and cause hot flashes. Prolactin stimulates enlargement of the mammary glands in preparation for milk production. ACTH stimulates maternal cortisol secretion, which contributes to fetal protein synthesis. In addition to the pituitary hormones, increased parathyroid levels mobilize calcium from parental bones for fetal use.

Weight Gain

The second and third trimesters of pregnancy are associated with dramatic changes in parental anatomy and physiology. The most obvious anatomical sign of pregnancy is the dramatic enlargement of the abdominal region, coupled with parental weight gain. This weight results from the growing fetus as well as the enlarged uterus, amniotic fluid, and placenta. Additional breast tissue and dramatically increased blood volume also contribute to weight gain. Surprisingly, fat storage accounts for only approximately 2.3 kg (5 lbs) in a normal pregnancy and serves as a reserve for the increased metabolic demand of breastfeeding.

During the first trimester, there’s no need to consume additional calories to maintain a healthy pregnancy. However, a weight gain of approximately 0.45 kg (1 lb) per month is common. During the second and third trimesters, a pregnant individual’s appetite increases, but it is only necessary to consume an additional 300 calories per day to support the growing fetus. Most individuals gain approximately 0.45 kg (1 lb) per week.

Changes in Organ Systems During Pregnancy

As the body adapts to pregnancy, characteristic physiologic changes occur. These changes can sometimes prompt symptoms often referred to collectively as the common discomforts of pregnancy.

Digestive and Urinary System Changes

Nausea and vomiting, sometimes triggered by an increased sensitivity to odors, are common during the first few weeks to months of pregnancy. This phenomenon is often referred to as “morning sickness,” although the nausea may persist all day. The source of pregnancy nausea is thought to be the increased circulation of pregnancy-related hormones, specifically circulating estrogen, progesterone, and hCG. Decreased intestinal peristalsis may also contribute to nausea. By about week 12 of pregnancy, nausea typically subsides.

A common gastrointestinal complaint during the later stages of pregnancy is gastric reflux, or heartburn, which results from the upward, constrictive pressure of the growing uterus on the stomach. The same decreased peristalsis that may contribute to nausea in early pregnancy is also thought to be responsible for pregnancy-related constipation as pregnancy progresses.

The downward pressure of the uterus also compresses the urinary bladder, leading to frequent urination. The problem is exacerbated by increased urine production. In addition, the parental urinary system processes both parental and fetal wastes, further increasing the total volume of urine.

Circulatory System Changes

Blood volume increases substantially during pregnancy, so that by childbirth, it exceeds its preconception volume by 30 percent, or approximately 1–2 liters. The greater blood volume helps to manage the demands of fetal nourishment and fetal waste removal. In conjunction with increased blood volume, the pulse and blood pressure also rise moderately during pregnancy. As the fetus grows, the uterus compresses underlying pelvic blood vessels, hampering venous return from the legs and pelvic region. As a result, many pregnant individuals develop varicose veins or hemorrhoids.

Respiratory System Changes

During the second half of pregnancy, the respiratory minute volume (volume of gas inhaled or exhaled by the lungs per minute) increases by 50 percent to compensate for the oxygen demands of the fetus and the increased parental metabolic rate. The growing uterus exerts upward pressure on the diaphragm, decreasing the volume of each inspiration and potentially causing shortness of breath, or dyspnea. During the last several weeks of pregnancy, the pelvis becomes more elastic, and the fetus descends lower in a process called lightening . This typically ameliorates dyspnea.

The respiratory mucosa swell in response to increased blood flow during pregnancy, leading to nasal congestion and nose bleeds, particularly when the weather is cold and dry. Humidifier use and increased fluid intake are often recommended to counteract congestion.

Integumentary System Changes

Figure 2. The linea nigra, a dark medial line running from the umbilicus to the pubis, forms during pregnancy and persists for a few weeks following childbirth. The linea nigra shown here corresponds to a pregnancy that is 22 weeks along.

The dermis stretches extensively to accommodate the growing uterus, breast tissue, and fat deposits on the thighs and hips. Torn connective tissue beneath the dermis can cause striae (stretch marks) on the abdomen, which appear as red or purple marks during pregnancy that fade to a silvery white color in the months after childbirth.

An increase in melanocyte-stimulating hormone, in conjunction with estrogens, darkens the areolae and creates a line of pigment from the umbilicus to the pubis called the linea nigra (Figure 2). Melanin production during pregnancy may also darken or discolor skin on the face to create a chloasma, or “mask of pregnancy.”

Physiology of Labor

Childbirth, or parturition , typically occurs within a week of an individual’s due date, unless the individual is pregnant with more than one fetus, which usually causes early labor. As a pregnancy progresses into its final weeks, several physiological changes occur in response to hormones that trigger labor.

First, recall that progesterone inhibits uterine contractions throughout the first several months of pregnancy. As the pregnancy enters its seventh month, progesterone levels plateau and then drop. Estrogen levels, however, continue to rise in the parental circulation. The increasing ratio of estrogen to progesterone makes the myometrium (the uterine smooth muscle) more sensitive to stimuli that promote contractions (because progesterone no longer inhibits them). Moreover, in the eighth month of pregnancy, fetal cortisol rises, which boosts estrogen secretion by the placenta and further overpowers the uterine-calming effects of progesterone. Some individuals may feel the result of the decreasing levels of progesterone in late pregnancy as weak and irregular peristaltic Braxton Hicks contractions , also called false labor. These contractions can often be relieved with rest or hydration.

Figure 3. A positive feedback loop of hormones works to initiate labor.

A common sign that labor will be short is the so-called “bloody show.” During pregnancy, a plug of mucus accumulates in the cervical canal, blocking the entrance to the uterus. Approximately 1–2 days prior to the onset of true labor, this plug loosens and is expelled, along with a small amount of blood.

Meanwhile, the posterior pituitary has been boosting its secretion of oxytocin, a hormone that stimulates the contractions of labor. At the same time, the myometrium increases its sensitivity to oxytocin by expressing more receptors for this hormone. As labor nears, oxytocin begins to stimulate stronger, more painful uterine contractions, which—in a positive feedback loop—stimulate the secretion of prostaglandins from fetal membranes. Like oxytocin, prostaglandins also enhance uterine contractile strength. The fetal pituitary also secretes oxytocin, which increases prostaglandins even further. Given the importance of oxytocin and prostaglandins to the initiation and maintenance of labor, it is not surprising that, when a pregnancy is not progressing to labor and needs to be induced, a pharmaceutical version of these compounds (called pitocin) is administered by intravenous drip.

Finally, stretching of the myometrium and cervix by a full-term fetus in the vertex (head-down) position is regarded as a stimulant to uterine contractions. The sum of these changes initiates the regular contractions known as true labor , which become more powerful and more frequent with time. The pain of labor is attributed to myometrial hypoxia during uterine contractions.

Stages of Childbirth

The process of childbirth can be divided into three stages: cervical dilation, expulsion of the newborn, and afterbirth.

Cervical Dilation

For vaginal birth to occur, the cervix must dilate fully to 10 cm in diameter—wide enough to deliver the newborn’s head. The dilation stage is the longest stage of labor and typically takes 6–12 hours. However, it varies widely and may take minutes, hours, or days, depending in part on whether the individual has given birth before; in each subsequent labor, this stage tends to be shorter.

Figure 4. Click for a larger image. The stages of childbirth include Stage 1, early cervical dilation; Stage 2, full dilation and expulsion of the newborn; and Stage 3, delivery of the placenta and associated fetal membranes. (The position of the newborn’s shoulder is described relative to the parent.)

True labor progresses in a positive feedback loop in which uterine contractions stretch the cervix, causing it to dilate and efface, or become thinner. Cervical stretching induces reflexive uterine contractions that dilate and efface the cervix further. In addition, cervical dilation boosts oxytocin secretion from the pituitary, which in turn triggers more powerful uterine contractions. When labor begins, uterine contractions may occur only every 3–30 minutes and last only 20–40 seconds; however, by the end of this stage, contractions may occur as frequently as every 1.5–2 minutes and last for a full minute.

Each contraction sharply reduces oxygenated blood flow to the fetus. For this reason, it is critical that a period of relaxation occur after each contraction. Fetal distress, measured as a sustained decrease or increase in the fetal heart rate, can result from severe contractions that are too powerful or lengthy for oxygenated blood to be restored to the fetus. Such a situation can be cause for an emergency birth with vacuum, forceps, or surgically by Caesarian section.

The amniotic membranes rupture before the onset of labor in about 12 percent of women; they typically rupture at the end of the dilation stage in response to excessive pressure from the fetal head entering the birth canal.

Expulsion Stage

The expulsion stage begins when the fetal head enters the birth canal and ends with birth of the newborn. It typically takes up to 2 hours, but it can last longer or be completed in minutes, depending in part on the orientation of the fetus. The vertex presentation known as the occiput anterior vertex is the most common presentation and is associated with the greatest ease of vaginal birth. The fetus faces the parental spinal cord and the smallest part of the head (the posterior aspect called the occiput) exits the birth canal first.

In fewer than 5 percent of births, the infant is oriented in the breech presentation, or buttocks down. In a complete breech, both legs are crossed and oriented downward. In a frank breech presentation, the legs are oriented upward. Before the 1960s, it was common for breech presentations to be delivered vaginally. Today, most breech births are accomplished by Caesarian section.

Vaginal birth is associated with significant stretching of the vaginal canal, the cervix, and the perineum. Until recent decades, it was routine procedure for an obstetrician to numb the perineum and perform an episiotomy , an incision in the posterior vaginal wall and perineum. The perineum is now more commonly allowed to tear on its own during birth. Both an episiotomy and a perineal tear need to be sutured shortly after birth to ensure optimal healing. Although suturing the jagged edges of a perineal tear may be more difficult than suturing an episiotomy, tears heal more quickly, are less painful, and are associated with less damage to the muscles around the vagina and rectum.

Upon birth of the newborn’s head, an obstetrician will aspirate mucus from the mouth and nose before the newborn’s first breath. Once the head is birthed, the rest of the body usually follows quickly. The umbilical cord is then double-clamped, and a cut is made between the clamps. This completes the second stage of childbirth.

The delivery of the placenta and associated membranes, commonly referred to as the afterbirth , marks the final stage of childbirth. After expulsion of the newborn, the myometrium continues to contract. This movement shears the placenta from the back of the uterine wall. It is then easily delivered through the vagina. Continued uterine contractions then reduce blood loss from the site of the placenta. Delivery of the placenta marks the beginning of the postpartum period—the period of approximately 6 weeks immediately following childbirth during which the parent’s body gradually returns to a non-pregnant state. If the placenta does not birth spontaneously within approximately 30 minutes, it is considered retained, and the obstetrician may attempt manual removal. If this is not successful, surgery may be required.

It is important that the obstetrician examines the expelled placenta and fetal membranes to ensure that they are intact. If fragments of the placenta remain in the uterus, they can cause postpartum hemorrhage. Uterine contractions continue for several hours after birth to return the uterus to its pre-pregnancy size in a process called involution , which also allows the parent’s abdominal organs to return to their pre-pregnancy locations. Breastfeeding facilitates this process.

Although postpartum uterine contractions limit blood loss from the detachment of the placenta, the parent does experience a postpartum vaginal discharge called lochia . This is made up of uterine lining cells, erythrocytes, leukocytes, and other debris. Thick, dark, lochia rubra (red lochia) typically continues for 2–3 days, and is replaced by lochia serosa, a thinner, pinkish form that continues until about the tenth postpartum day. After this period, a scant, creamy, or watery discharge called lochia alba (white lochia) may continue for another 1–2 weeks.

Chapter Review

Hormones (especially estrogens, progesterone, and hCG) secreted by the corpus luteum and later by the placenta are responsible for most of the changes experienced during pregnancy. Estrogen maintains the pregnancy, promotes fetal viability, and stimulates tissue growth in the parent and developing fetus. Progesterone prevents new ovarian follicles from developing and suppresses uterine contractility.

Pregnancy weight gain primarily occurs in the breasts and abdominal region. Nausea, heartburn, and frequent urination are common during pregnancy. Gestational parent blood volume increases by 30 percent during pregnancy and respiratory minute volume increases by 50 percent. The skin may develop stretch marks and melanin production may increase.

Toward the late stages of pregnancy, a drop in progesterone and stretching forces from the fetus lead to increasing uterine irritability and prompt labor. Contractions serve to dilate the cervix and expel the newborn. Delivery of the placenta and associated fetal membranes follows.

Answer the question(s) below to see how well you understand the topics covered in the previous section.

Critical Thinking Questions

• Devin is 35 weeks pregnant with their first child when they arrive at the birthing unit reporting that they believe they are in labor. They state that they have been experiencing diffuse, mild contractions for the past few hours. Examination reveals, however, that the plug of mucus blocking their cervix is intact and their cervix has not yet begun to dilate. Devin is advised to return home. Why?
• Janine is 41 weeks pregnant with her first child when she arrives at the birthing unit reporting that she believes she has been in labor “for days” but that “it’s just not going anywhere.” During the clinical exam, she experiences a few mild contractions, each lasting about 15–20 seconds; however, her cervix is found to be only 2 cm dilated, and the amniotic sac is intact. Janine is admitted to the birthing unit and an IV infusion of pitocin is started. Why?
• Devin is very likely experiencing Braxton Hicks contractions, also known as false labor. These are mild contractions that do not promote cervical dilation and are not associated with impending birth. They will probably dissipate with rest.
• Janine is 41 weeks pregnant, and the mild contractions she has been experiencing “for days” have dilated her cervix to 2 cm. These facts suggest that she is in labor, but that the labor is not progressing appropriately. Pitocin is a pharmaceutical preparation of synthetic prostaglandins and oxytocin, which will increase the frequency and strength of her contractions and help her labor to progress to birth.

afterbirth: third stage of childbirth in which the placenta and associated fetal membranes are expelled

Braxton Hicks contractions: weak and irregular peristaltic contractions that can occur in the second and third trimesters; they do not indicate that childbirth is imminent

dilation: first stage of childbirth, involving an increase in cervical diameter

episiotomy: incision made in the posterior vaginal wall and perineum that facilitates vaginal birth

expulsion: second stage of childbirth, during which the parent bears down with contractions; this stage ends in birth

involution: postpartum shrinkage of the uterus back to its pre-pregnancy volume

lightening: descent of the fetus lower into the pelvis in late pregnancy; also called “dropping”

lochia: postpartum vaginal discharge that begins as blood and ends as a whitish discharge; the end of lochia signals that the site of placental attachment has healed

parturition: childbirth

trimester: division of the duration of a pregnancy into three 3-month terms

true labor: regular contractions that immediately precede childbirth; they do not abate with hydration or rest, and they become more frequent and powerful with time

• Anatomy & Physiology. Provided by : OpenStax CNX. Located at : http://cnx.org/contents/[email protected] . License : CC BY: Attribution . License Terms : Download for free at http://cnx.org/contents/[email protected]

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Understanding Uterine Anomalies

One in 20 women will have some kind of uterine abnormality. Most won’t realize they have the condition until there are complications with a pregnancy. On this episode of “The Seven Domains of Women’s Health,” Dr. Kirtly Jones speaks about uterine anomalies: What they are, how they impact women, and available options for treating and living with uterine abnormalities.

Episode Transcript

Dr. Jones: When is a human uterus like a horse or a cat uterus? Well, it's not, except when it is. This is Dr. Kirtly Jones from obstetrics and gynecology at the University of Utah Health and we're talking about uterine anomalies today on the Scope.

Announcer: Covering all aspects of women's health, this is the Seven Domains of Women's Health with Dr. Kirtly Jones on The Scope.

Uterus Anatomy

Dr. Jones: The human uterus is shaped sort of like a light bulb, the old-fashioned kind. The metal part at the bottom is the cervix, which keeps the uterus anchored in the pelvis and keeps the baby in. The bulb part is the actual uterus. Inside the bulb is the uterine cavity where the baby grows and it's normally shaped like an upside down triangle. Two corners at the top of the triangle point into the fallopian tubes and one corner points down into the cervix. The uterine cavity is flat like an envelope until it's filled with the pregnancy.

What Is a Uterine Anomaly (or Abnormality)?

Congenital uterine anomalies, malformations of the uterus that occur during fetal development, are common. About five percent of women, one in 20, will have some kind of uterine abnormality. Although many women have a uterus that slightly abnormally shaped and they may never know about or have any problems. Some uterine shapes can cause recurrent miscarriages or premature births or infertility.

Rarely, about one in 5,000, women have two uteruses and two cervices and two vaginas and about one in 1000 women have no uterus, no cervix, and no vagina. Understanding how the uterus develops is helpful here. In human and mammal development, there are two tubes that come together in the pelvis. These two tubes fuse together at the lower end and the middle of the fuse two tubes dissolves to make one uterine cavity and one cervix with the two fallopian tubes at the top.

Now, this is something that's really better on video than audio. So let's do an experiment. Imagine yourself taking two foam tubes, one in each hand. The kind of floppy foam tubes. So you're holding these foam tubes, you bring your hands together and the foam tubes in your hands at the lower part of these tubes fuse and the upper parts are kind of floppy on the sides. Those are the fallopian tubes so where they fused together, that makes the uterus.

Now if that fusion doesn't happen normally, if you got those two foam tubes in your hands, you get to uteruses and two cervices. If at all fuses and dissolves, your hands come together and you get no uterus or cervix. If it fuses but doesn't dissolve completely, you can have a uterus that's Y shaped with two horns or uterus with the wall down the middle.

Men, by the way, had these two tubes when they were developing but males make a chemical that makes the entire uterine system disappear well before they're born. That's why guys don't have a uterus.

How Does a Woman Find Out if She Has a Uterine Anomaly?

Women without a uterus or cervix don't have periods so that's usually discovered when they're teenagers. We want to end with just a little dent on the top of the triangular uterine cavity, like horses, have about we call arcuate uterus or heart-shaped uterus and they may never know it as it doesn't cause problems.

Bicornuate Uterus

Women with the Y-shaped uterus, we call it bicornuate, and that's the normal shape for mammals to have lots of little babies like cats, may find out that this is the uterus when they have premature babies. Women with the wall in the uterine cavity, called a septum, may find out that they when they have recurrent miscarriages.

There are many other less common uterine anomalies, but what do we do about this? Well, the majority of women with uterine anomalies have no problems except with pregnancy. We don't recommend that all baby girls or young women have imaging of the uterus to find out if it's normally shaped or not.

Some women find out that they have an abnormally shaped uterus when they have a cesarean section, maybe for a breech baby, and an abnormally shaped uterus is more likely to lead to a breech presentation of the baby.

Women who have had a very premature baby for no good reason may be advised to get imaging of their uterus. Depending on the problem, this might be done with a special kind of ultrasound or an X-ray that puts a special fluid in the uterus so the uterine cavity can be evaluated on a screen or an MRI.

Women with recurrent miscarriages usually get some kind of imaging to see if they might have a septum or wall down the middle of their uterus. The good news is that reproductive medicine specialists can surgically remove this wall with excellent results for the next pregnancy.

What Kind of Doctor Should You See for a Uterine Anomaly?

If someone has a uterine anomaly, what kind of doctor should they see? At the U, we have a team of reproductive endocrinologists, specialists in reproductive problems, who often team up with our high-risk pregnancy specialists to work out a plan for each woman and her uterine problem.

Surgical correction of the problem is often is an option. When there's no way to correct the problem, we often talk about gestational surrogacy where we use someone else's uterus to carry your biological baby, which we can do at the University of Utah Hospital in our Center for Reproductive Medicine.

Human development is amazing and interesting and, of course, I think the reproductive system is the coolest. But when things don't go exactly right, there are specialists who have experience and probably they can help you out. And thanks for joining us on The Scope.

Announcer: TheScopeRadio.com is University of Utah Health Radio. If you like what you heard be sure to get our latest content by following us on Facebook, just click on the Facebook icon at the ScopeRadio.com.

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Uterine Prolapse in Pregnancy: A Review

Norby, Nicole MD ∗ ; Murchison, Amanda B. MD † ; McLeish, Shian MD ∗ ; Ghahremani, Taylor MD ‡ ; Whitham, Megan MD § ; Magann, Everett F. MD ∥

∗ Resident, Department of Obstetrics and Gynecology, Virginia Tech Carilion School of Medicine, Roanoke, VA

† Associate Professor, Residency Director, Department of Obstetrics and Gynecology, Virginia Tech Carilion School of Medicine, Roanoke, VA

‡ MFM Fellow, The University of Arkansas for Medical Sciences, Little Rock, AR

§ Assistant Professor, Department of Obstetrics and Gynecology, Virginia Tech Carilion School of Medicine, Roanoke, VA

∥ Professor MFM Fellowship Director, University of Arkansas for Medical Sciences, Little Rock, AR

All authors, faculty, and staff have no relevant financial relationships with any ineligible organizations regarding this educational activity.

Correspondence requests to: Everett F. Magann MD, Department of Obstetrics and Gynecology, University of Arkansas for Medical Sciences, 4301 W Markham St, Slot #518, Little Rock, AR 72205. E-mail: [email protected] .

Supplemental digital content is available for this article. Direct URL citations appear in the printed text, and links to the digital files are provided in the HTML text of this article on the journal’s Web site ( www.obgynsurvey.com ).

Importance 

Although not a common occurrence, uterine prolapse during pregnancy can have significant effects for pregnancy outcomes and quality of life of maternal patients. Most data about management exist as case reports; a review of these cases provides some guidance about treatment options.

Objectives 

This review examines current literature about uterine prolapse during pregnancy to assess current information about this condition, prevalence, diagnosis, management, and outcomes.

Evidence Acquisition 

Electronic databases (PubMed and Embase) were searched using terms “uterine prolapse” AND “pregnancy” AND “etiology” OR “risk factors” OR “diagnosis” OR “therapy” OR “management” limited to the English language and between the years 1980 and October 31, 2022.

Results 

Upon review of 475 articles, 48 relevant articles were included as well as 6 relevant articles found on additional literature review for a total of 54 articles. Of those articles, 62 individual cases of uterine prolapse in pregnancy were reviewed including pregnancy complications, mode of delivery, and outcomes. Prevalence was noted to be rare, but much more common in second and subsequent pregnancies. Most diagnoses were made based on symptomatic prolapse on examination. Management strategies included bed rest, pessary use, and surgery (typically during the early second trimester). Complications included preterm delivery, patient discomfort, urinary retention, and urinary tract infection. Delivery methods included both cesarean and vaginal deliveries.

Conclusions 

Although a rare condition, uterine prolapse in pregnancy is readily diagnosed on examination. Reasonable conservative management strategies include observation, attempted reduction of prolapse, and pessary use; if these measures fail, surgical treatment is an option.

Relevance 

Our review compiles literature and known cases of uterine prolapse during pregnancy and current evidence about prevalence, diagnosis, management, outcomes, and complications of uterine prolapse during pregnancy in order to inform our target audience in their clinical practice.

Target Audience 

Obstetricians and gynecologist, family physicians.

Learning Objectives 

After completing this learning activity, the participant should be able to describe the prevalence of uterine prolapse during pregnancy, potential at-risk populations, and presenting symptoms; identify management strategies for uterine prolapse during pregnancy including both surgical and conservative approaches; and assess possible complications of uterine prolapse during pregnancy.

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• Ectopic pregnancy

On this page

When to see a doctor, risk factors, complications.

Pregnancy begins with a fertilized egg. Normally, the fertilized egg attaches to the lining of the uterus. An ectopic pregnancy occurs when a fertilized egg implants and grows outside the main cavity of the uterus.

An ectopic pregnancy most often occurs in a fallopian tube, which carries eggs from the ovaries to the uterus. This type of ectopic pregnancy is called a tubal pregnancy. Sometimes, an ectopic pregnancy occurs in other areas of the body, such as the ovary, abdominal cavity or the lower part of the uterus (cervix), which connects to the vagina.

An ectopic pregnancy can't proceed normally. The fertilized egg can't survive, and the growing tissue may cause life-threatening bleeding, if left untreated.

In a healthy pregnancy, the fertilized egg attaches itself to the lining of the uterus. In an ectopic pregnancy, the egg attaches itself somewhere outside the uterus usually to the inside of a fallopian tube.

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You may not notice any symptoms at first. However, some women who have an ectopic pregnancy have the usual early signs or symptoms of pregnancy — a missed period, breast tenderness and nausea.

If you take a pregnancy test, the result will be positive. Still, an ectopic pregnancy can't continue as normal.

As the fertilized egg grows in the improper place, signs and symptoms become more noticeable.

Early warning of ectopic pregnancy

Often, the first warning signs of an ectopic pregnancy are light vaginal bleeding and pelvic pain.

If blood leaks from the fallopian tube, you may feel shoulder pain or an urge to have a bowel movement. Your specific symptoms depend on where the blood collects and which nerves are irritated.

Emergency symptoms

If the fertilized egg continues to grow in the fallopian tube, it can cause the tube to rupture. Heavy bleeding inside the abdomen is likely. Symptoms of this life-threatening event include extreme lightheadedness, fainting and shock.

Seek emergency medical help if you have any signs or symptoms of an ectopic pregnancy, including:

• Severe abdominal or pelvic pain accompanied by vaginal bleeding
• Extreme lightheadedness or fainting
• Shoulder pain

From Mayo Clinic to your inbox

A tubal pregnancy — the most common type of ectopic pregnancy — happens when a fertilized egg gets stuck on its way to the uterus, often because the fallopian tube is damaged by inflammation or is misshapen. Hormonal imbalances or abnormal development of the fertilized egg also might play a role.

Some things that make you more likely to have an ectopic pregnancy are:

• Previous ectopic pregnancy. If you've had this type of pregnancy before, you're more likely to have another.
• Inflammation or infection. Sexually transmitted infections, such as gonorrhea or chlamydia, can cause inflammation in the tubes and other nearby organs, and increase your risk of an ectopic pregnancy.
• Fertility treatments. Some research suggests that women who have in vitro fertilization (IVF) or similar treatments are more likely to have an ectopic pregnancy. Infertility itself may also raise your risk.
• Tubal surgery. Surgery to correct a closed or damaged fallopian tube can increase the risk of an ectopic pregnancy.
• Choice of birth control. The chance of getting pregnant while using an intrauterine device (IUD) is rare. However, if you do get pregnant with an intrauterine device (IUD) in place, it's more likely to be ectopic. Tubal ligation, a permanent method of birth control commonly known as "having your tubes tied," also raises your risk, if you become pregnant after this procedure.
• Smoking. Cigarette smoking just before you get pregnant can increase the risk of an ectopic pregnancy. The more you smoke, the greater the risk.

An ectopic pregnancy can cause your fallopian tube to burst open. Without treatment, the ruptured tube can lead to life-threatening bleeding.

There's no way to prevent an ectopic pregnancy, but here are some ways to decrease your risk:

• Limiting the number of sexual partners and using a condom during sex helps to prevent sexually transmitted infections and may reduce the risk of pelvic inflammatory disease.
• Don't smoke. If you do, quit before you try to get pregnant.

Mar 12, 2022

• Cunningham FG, et al., eds. Implantation and placental development. In: Williams Obstetrics. 25th ed. McGraw-Hill Education; 2018. https://accessmedicine.mhmedical.com. Accessed Dec. 4, 2019.
• Tulandi T. Ectopic pregnancy: Epidemiology, risk factors, and anatomic sites. https://www.uptodate.com/contents/search. Accessed Dec. 4, 2019.
• Cunningham FG, et al., eds. Ectopic pregnancy. In: Williams Obstetrics. 25th ed. McGraw-Hill Education; 2018. https://accessmedicine.mhmedical.com. Accessed Dec. 4, 2019.
• Frequently asked questions. Pregnancy FAQ 155. Ectopic pregnancy. American College of Obstetricians and Gynecologists. https://www.acog.org/Patients/FAQs/Ectopic-Pregnancy. Accessed Dec. 4, 2019.
• Tulandi T. Ectopic pregnancy: Clinical manifestations and diagnosis. https://www.uptodate.com/contents/search. Accessed Dec. 29, 2017.
• Burnett TL (expert opinion). Mayo Clinic. Dec. 4, 2019.
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• Ectopic pregnancy symptoms & causes

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• Volume 14, Issue 3
• Uterine didelphys: diagnosis, management and pregnancy outcome
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• Clare Margaret Crowley ,
• http://orcid.org/0000-0001-9547-4417 Karim Botros ,
• Ibrahim Fawzy Hegazy and
• Edward O'Donnell
• Obstetrics and Gynaecology , University Hospital Waterford , Waterford , Ireland
• Correspondence to Dr Clare Margaret Crowley; crowlecl{at}tcd.ie

This report addresses and discusses two cases of uterine didelphys in pregnancy. The first case describes the diagnosis, management and subsequent pregnancies in a 28-year-old woman, para 2, with known didelphys uterus, left-obstructed hemi-vagina and ipsilateral renal agenesis. This uterine anomaly was diagnosed at 13 years of age, after pelvic imaging identified a haematocolpos and two uteri. To drain this haematocolpos, a hymenectomy was performed. In the second case, an incidental finding of uterine didelphys and vaginal septum in a 28-year-old primigravida is described. Both patients delivered healthy male infants at term via emergency and planned lower segment caesarean sections, indicating women with major uterine anomalies can have successful obstetric outcomes.

• obstetrics and gynaecology
• reproductive medicine

https://doi.org/10.1136/bcr-2021-242233

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Contributors CMC wrote the report. KB obtained patient consent and critically appraised the report. IFH further evaluated the report. EOD critically appraised the report and was the primary physician to both patients.

Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

Competing interests None declared.

Provenance and peer review Not commissioned; externally peer reviewed.

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Diagnosis and Management of Uterine Rupture in the Third Trimester of Pregnancy: A Case Series and Literature Review

Mrooj m abdulmane.

1 Obstetrics and Gynecology, King Fahad Armed Forces Hospital, Jeddah, SAU

Omar M Sheikhali

2 Obstetrics and Gynecology, Ibn Sina National College, Jeddah, SAU

Raghad M Alhowaidi

3 Obstetrics and Gynecology, King Abdulaziz University Faculty of Medicine, Jeddah, SAU

Afshan Qazi

Khalid ghazi.

Background: Uterine rupture is associated with clinically significant uterine bleeding, fetal distress, expulsion or protrusion of the fetus, placenta or both into the abdominal cavity requiring prompt cesarean delivery and uterine repair or hysterectomy. Previous cesarean section is the most common risk factor. The most consistent early indicator of it is the onset of prolonged and profound fetal bradycardia.

Objective: In this study, we present six cases of uterine rupture highlighting risk factors, and challenges in diagnosis and management, along with a review of the literature.

Method: A retrospective case series identified eight cases during the five-year study period. All cases from January 1, 2018 to December 31, 2022 were reviewed. Cases with multiple previous cesarean sections were excluded.

Result: Six cases meeting the study criteria were included in our case series. Uterine rupture was a rare occurrence with a prevalence of nine in 31,315 births representing 0.03% of deliveries. No maternal mortality or need for hysterectomy occurred in our study. Fifty percent of uterine ruptures were associated with stillbirths. The most common risk factor was a previous cesarean section in 83.3%. The most common presenting sign was non-reassuring fetal status patterns in 66.6%. A single case had a silent rupture.

Conclusion: Signs and symptoms of uterine rupture are nonspecific making diagnosis challenging. Delay in definitive management causes significant fetal morbidity and mortality. For best outcomes, vaginal birth after a previous cesarean section needs close monitoring in appropriately prepared units with the ability to perform immediate cesarean delivery and provide advanced neonatal support.

Introduction

Uterine rupture (UR) is an exceedingly rare and dreaded event that may result in extensive uterine damage requiring a hysterectomy and may even lead to fetal or maternal death [ 1 - 3 ]. It is reported to occur in 1:2,500 to 1:5,000 births, although variations have been reported over time and between different demographic groups [ 2 , 4 - 6 ]. Two types of UR exist, the less common complete type which results in a direct connection between the uterine cavity and the peritoneal space due to the involvement of all uterine wall layers, and the more common incomplete type where the uterus remains covered by a portion of visceral peritoneum [ 7 ].

UR most commonly arises in the setting of a scarred uterus [ 7 - 9 ]. Studies demonstrate a change in the etiology of UR with decreasing cases occurring as a result of manipulative obstetric procedures and increasing prevalence as a consequence of the increased popularity of cesarean section (CS) deliveries [ 2 , 6 , 10 , 11 ]. Over the last few decades, the recommended rate of CS deliveries set by the WHO has been surpassed especially in developed countries [ 12 - 14 ]. Diagnosis of UR should be suspected in the setting of altered fetal heart rate patterns or symptoms of vaginal bleeding, maternal tachycardia, or unusual pain during labor [ 2 , 10 ]. In this case series, we will present six cases of UR that occurred in our hospital and share our experience in diagnosis, management, and outcomes as well as a review of the associated literature.

Materials and methods

A search of the Obstetrics and Gynecology Department’s morbidity and mortality records in our tertiary care hospital from January 1, 2018 to December 31, 2022 was performed to identify all cases of UR. A total of nine cases were discovered and a review of the medical records was performed maintaining complete confidentiality and animosity. All patients who presented throughout the study duration who had one or no prior CS were included. Patients who had multiple CSs were excluded from the study as per our exclusion criteria.

Our case series showed UR to be a rare complication of delivery with a prevalence of 0.03% (nine in 31,315 births). No maternal mortality occurred in our study and no hysterectomy was required as a result of UR. 50% of UR were associated with stillbirths. Known risk factors of uterine rupture encountered in our patients included previous CS which was seen in 83.3%, multiparity in 33%, obstructed labor in 33%, induction with prostaglandin in 16.2%, and augmentation with oxytocin in 16.2%. No cases were found to have uterine anomalies and no cases of malpresentation were seen. The most common presenting sign for UR in our study was abnormal or non-reassuring fetal status patterns which were seen in 66.6%. We had a single case that presented with a silent UR.

A 38-year-old gravida 5, para 4 woman with 39+4 gestational weeks of pregnancy was admitted for delivery. Her medical history was free of any medical ailments, surgical history included one CS less than three years ago at 32 gestational weeks due to antepartum hemorrhage and placenta previa during her first pregnancy. Her second to fourth pregnancies were successfully delivered by vaginal birth after cesarean (VBAC). A physical examination showed stable vital signs, her cervix was found to be 3 centimeters dilated, 70% effaced, and vertex at -3 station. Cardiotocographic monitoring (CTG) revealed a reassuring fetal status pattern. She reported that the pain was transiently alleviated after she received meperidine for the labor pain. Her vital signs remained stable, and the heart rate of the fetus was 140 to 145 beats/minute. Two hours later, her ultrasound indicated probable uterine rupture and a non-viable fetus with a breech presentation which was previously cephalic. Repeat evaluation revealed the absence of abdominal pain or PV bleeding and her cervical OS was found to be closed. Consequently, an immediate emergency CS was performed. Intraoperatively, a large amount of hemoperitoneum was noted before a complete rupture of her previous CS scar was observed, which had extended to the cervix with most of the placenta already expelled from it. A fresh stillbirth with an Apgar score of 0-0 weighing 2.8 kg was delivered. The uterus was conservatively repaired in two layers. The mother had an uneventful recovery postoperatively. This case is extremely unique due to the occurrence of a silent UR.

A case of spontaneous onset of labor in a 29-year-old gravida 2, para 1 woman with 39+3 gestational weeks of pregnancy, with a history of a previous CS delivery was admitted for elective CS due to uncontrolled blood sugar profile. Her medical history was free of any medical conditions except for gestational diabetes, her surgical history included one CS at term two years ago due to fetal distress during her first pregnancy. Her physical examination showed stable vital signs. Examination revealed that she had gone into spontaneous labor with her cervix being 3 centimeters dilated, 50% effaced, and the vertex at -3 station. CTG revealed a reassuring fetal status pattern. Consequently, after a discussion with the patient she elected to deliver vaginally. Following her evaluation an artificial rupture of membrane (ARM) was performed for augmentation and she progressed smoothly to a fully dilated cervix with vertex at -2 station. Suddenly during labor, her CTG revealed fetal bradycardia. As a result, UR was suspected, and an emergency CS was immediately performed. A UR of the entire previous scar was noted. A live baby girl with an Apgar score of 8-9 weighing 3.2 kg was delivered. The uterus was conservatively repaired, and the mother had an uneventful recovery.

Case three  

A 25-year-old gravida 2, para 1 woman at 35+4 gestational weeks of pregnancy was admitted due to a non-reassuring CTG. Her medical history was free of any medical illnesses and her surgical history included a CS at term due to fetal distress two years prior to presentation. She had presented to our department with false labor pain. Her physical examination showed stable vital signs and vaginal examination showed her cervix to be 1 centimeter dilated, 80% effaced, and the vertex at -3 station. CTG revealed a non-reassuring fetal status pattern. Following her evaluation, controlled ARM was done for augmentation and she progressed smoothly to a fully dilated cervix, zero station with caput. An hour later her CTG recorded atypical variable decelerations that did not recover. Consequently, an emergency CS was decided upon as instrumental delivery was not considered appropriate. Intraoperatively a large amount of hemoperitoneum was noted. A complete rupture of her previous CS scar was observed. A live baby boy with an Apgar score of 6-7 weighing 2.8 kg was delivered. The uterus was conservatively repaired and our patient recovered well with no complications.

Case four  

A 27-year-old woman who was gravida 3, para 1, and abortus 1 presented at 33+1 weeks to our emergency department with reduced fetal movements. As a result, she was admitted for fetal monitoring. Her history revealed that she was medically free and her surgical history included a CS at term due to fetal distress three years before her presentation. Evaluation of our patient’s CTG monitoring revealed a pathological CTG pattern of fetal bradycardia and her physical examination showed stable vital signs. A vaginal examination was foregone as her pathological CTG prompted an emergency CS. Intraoperatively, a complete rupture of her previous CS scar was noted. A fresh stillbirth with an Apgar score of 0-0 and weighing 1.9 kg was delivered. The uterus was conservatively repaired in two layers. Her recovery period went smoothly with no complications.

A 44-year-old grand multiparous woman at 40 gestational weeks of pregnancy was admitted for fetal surveillance due to her antenatal ultrasound showing high resistance fetal umbilical arterial pulsatility index Doppler, as well as a transverse fetal lie. Obstetrical history showed that she was gravida 9, para 7, and abortion 1. Her medical history was free of any medical ailments except for gestational diabetes, surgical history was free. A physical examination showed stable vital signs. On her second day of admission, the fetus’s presentation became cephalic and as a result, she was planned for induction of labor with a prostaglandin agent. She progressed to 4 centimeters dilated, 50% effaced, and the vertex at -3 station. Following her evaluation an ARM was done for augmentation and her CTG demonstrated a reassuring fetal status pattern. She progressed smoothly to a fully dilated cervix, vertex -1, for more than 1 hour. Consequently, oxytocin augmentation was started, however, no further progress had occurred after 1 hour. Her CTG remained reassuring and emergency CS was performed for second-stage arrest. Intraoperatively, a right anterior uterine wall complete rupture was observed with the baby found in the peritoneal cavity. A fresh stillbirth with an Apgar score of 0-0 and weighing 3.9 kg was delivered. The uterus was repaired conservatively and our patient had an uneventful recovery.

Case six  

A 36-year-old woman in her third pregnancy presented in early labor. Her history showed that she was at 39+2 gestational weeks of pregnancy. She was medically free with a surgical history of one CS at term due to twin pregnancy during her first pregnancy, 10 years ago. Her second pregnancy was successfully delivered by VBAC. Her physical examination showed stable vital signs and vaginal examination showed her cervix to be 2 centimeters dilated, 90% effaced, and the vertex at -2 station. CTG revealed a reassuring fetal status pattern. After her evaluation, she was admitted for vaginal. During her admission, ARM was done for augmentation, and she progressed smoothly to 9 centimeters, -1 station; however, no further progress was noted over the ensuing four hours. Her CTG was still demonstrating a reassuring fetal status pattern. Accordingly, an emergency CS was performed for the failure of labor to progress. Intraoperatively an incomplete rupture of her previous CS scar was observed, and a live baby boy delivered with an Apgar score of 8-9 and weighing 2.9 kg was delivered. Her uterus was repaired conservatively, and she had an uneventful recovery period.

Over the last few decades there has been increasing worldwide popularity and performance of CS [ 15 ]. Internationally CS birth rates have seen a four-fold increase in less than 20 years [ 16 , 17 ]. The current rate of CS globally is 21.1% ranging from 5% in sub-Saharan Africa to 42.8% in Latin America [ 17 ]. The substantial rise in CS rates has led to an increased number of women at risk of complications secondary to a scarred uterus including UR [ 9 , 18 , 19 ]. Our center is no different, over the study period from January 1, 2018 to December 31, 2022, we had an average of 6,263 deliveries with 33.7% delivered by CS. Current projections show that by 2030 the worldwide rate for CS delivery will be 28.5% with rates as high as 63.4% in Eastern Asia [ 17 ].

There is considerable debate and dilemma concerning vaginal births after lower segment CS, paramount to the debate is the concern over UR [ 20 - 23 ]. Most studies indicate that the majority of URs arising from scarred uterus occur in parturient women who have delivered via CS in the past [ 2 , 10 ]. Our study demonstrated similar findings, 83.3% of UR cases were seen in the presence of a scarred uterus following a CS. It is important for Obstetricians to keep in mind that after performing CS they are exposing women to an increased individual risk of UR or CS hysterectomy [ 22 , 24 ]. We recommend counseling patients adequately regarding future risks of UR following CS and having lower thresholds for suspecting UR in women who have undergone prior CS.

Studies looking at women with previous CS deliveries demonstrated that women with two or more CS deliveries were at a higher risk of UR [ 25 ]. Limited studies looking at UR in women with two or more CS deliveries found the incidence to range between 0.9% and 3.7% [ 25 - 27 ]. Our case series also highlights the heightened risk of UR in women with previous CS as all patients had a positive history with the exception of a single case. During our review of UR cases in our center we encountered two cases of UR, one in a patient with two previous CS deliveries and the other with four previous CS deliveries; however, both were excluded as per our study criteria. Other risk factors identified in the literature include allowing a trial of labor after CS, instrumental deliveries, or when excessive induction is conducted [ 28 - 32 ]. All women in our case series were allowed a trial of labor after CS except for Case 5, emphasizing its clear association with UR and the heightened risk carried out in such cases. However, no instrumental deliveries were encountered.

Studies have found that the risk for UR decreases in women who have had a successful VBAC [ 32 , 33 ]. A great degree of caution should be taken when managing a trial of labor in women with a previous uterine scar, especially if labor has failed to progress [ 34 ]. Although it is difficult to conclude a solid association with certainty from our case series, 33.3% of patients had UR following VBAC, Case 1 had three successful VBACs before suffering UR, and Case 6 also suffered a UR after VBAC. Despite a history of successful VBAC we strongly recommend that all women with previous CS and a consequent uterine scar be closely monitored with intense vigilance for the possible occurrence of UR and that patients should have a decreased thresh-hold for being converted to delivery by CS. Our recommendation is supported by a study that calculated that when labor dystocia; defined as cervical dilatation lower than the 10th percentile and arrested for more than two hours occurred, performing CS would have helped avoid more than 40% of UR [ 35 ]. VBAC is only recommended in select cases [ 36 , 37 ]. Careful selection increases the number of successful VBACs as well as decreases maternal complications [ 22 ].

Currently, the most effective way of identifying patients at risk of UR remains clinical evaluation as evidenced by studies looking at lower-segment ultrasonography which failed to demonstrate a superiority to clinical evaluation [ 38 - 40 ]. With the widespread use of electronic fetal monitoring, fetal heart rate abnormalities have become the most common presenting feature of UR [ 2 , 10 ]. Fetal heart rate abnormalities may include variable and or late decelerations which occur before the onset of fetal bradycardia; however, no specific fetal heart rate or uterine activity pattern has been identified to indicate UR [ 41 , 42 ]. Our case series also found the importance of fetal heart rate abnormalities as a presenting sign of UR, with fetal heart abnormalities being the first sign to raise suspicion of UR in 66.6% of cases. We suggest that any woman in the active phase of labor should be on continuous fetal monitoring and should receive extensive clinical evaluation and prompt management at the first sign of abnormal pattern, including the possibility of UR, especially in the setting of VBAC.

Thankfully we had no cases of maternal mortality in our case series, with other studies from developed countries showing similar findings [ 2 , 6 , 34 ]. However, studies from developing countries reported maternal mortality rates ranging from 1% to 13% [ 42 , 43 ]. We believe that this is due to more advanced medical resources and diagnostic modalities available in developed countries allowing UR to be identified and managed adequately at an earlier stage. All women in our case series had successful repair of UR and none required hysterectomy. This is in contrast to other studies which report a hysterectomy rate following UR raging between 13% and 33% [ 2 , 9 , 34 ]. Fetal mortality occurred in 50% of our patients. Other studies showed fetal mortality rates ranging between 19% and 60% of cases [ 2 , 34 ]. A systematic review found fetal mortality to be 5% in cases of symptomatic UR [ 9 ]. We attribute the variations in rates of hysterectomy and fetal mortality following UR to the evolution of medical services in newer studies compared to older ones, as well as the differences in socio-economic statuses allowing earlier recognition between the various countries where the studies were conducted.

Conclusions

In this case series, we aim to raise awareness regarding the signs and symptoms of UR, which are typically nonspecific, making diagnosis difficult in the absence of a high index of clinical suspicion. Any delay in definitive therapy may carry significant morbidity and mortality for both the fetus and the mother. The inconsistent signs and the short time window for definitive intervention make UR a challenging event even for the most experienced of Obstetricians. We encourage frequent clinical assessment and continuous fetal monitoring to help identify this rare, but often catastrophic complication of pregnancy after previous CS. For the best outcome, VBAC needs to be appropriately managed in a well-staffed and equipped unit for possible immediate CS delivery and advanced neonatal support.

The authors have declared that no competing interests exist.

Human Ethics

Consent was obtained or waived by all participants in this study. The Research Ethics Committee of Armed Forces Hospitals, Jeddah issued approval REC 544

Animal Ethics

Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue.