What You’re Seeing: Sometimes, your doctor or midwife will ask for a test to check how well your baby is doing. One indicator of your baby-to-be’s well-being is a measurement of the amniotic fluid. This can also be part of a test called a biophysical profile, which will also include watching the baby’s various movements.
What the different baby positions in the womb mean during pregnancy
During pregnancy, a developing fetus will move into several positions. As labor approaches, most turn so that their head is down. If a fetus is lying horizontally, a cesarian delivery may be necessary.
The ideal position for a fetus just before labor is the anterior position — the fetus faces the pregnant person’s back, and the head points toward the ground.
Most fetuses settle into this position by the last month of pregnancy. The anterior position is also known as the vertex, cephalic, or occiput anterior position.
This position may reduce the chances of complications during pregnancy. Learn more about this and other fetal positions below.
A fetus might be in any of these positions:
- Left occiput anterior: The head is down, the fetus is facing the pregnant person’s back, and they are in the left side of the womb.
- Right occiput anterior: The position is the same as that above, but the fetus is in the womb’s right side.
- Posterior: The head is down, and the back is in line with the pregnant person’s.
- Transverse lie: The fetus is lying horizontally on its back.
- Breech: The fetus’s feet point down.
A fetus changes position many times throughout a pregnancy, but by the time of delivery, most are in the occiput anterior position.
The best position for the fetus before delivery is the anterior position. Most get into this position before labor begins.
The fetus’s head is down in the pelvis, facing the pregnant person’s back. The fetus’s back faces the person’s belly.
This means that the fetus’s head can tuck in, with the top pressing down on the cervix. This encourages it to open during labor.
Depending on where in the womb the fetus is, the doctor or midwife may describe the position as left occiput anterior, or LOA, or right occiput anterior, or ROA.
This is also known as the back-to-back position. The fetus’s head points down, and its back rests against the pregnant person’s back.
In this position, it can be difficult for the head to tuck in. This can make passing through the smallest part of the pelvis more challenging and lead to a slower labor and a backache for the pregnant person.
A fetus may be more likely to end up in this position if the person spends long periods sitting or lying down, which may be the case if a doctor recommends bed rest.
The back of a fetus’s body is heavier than the front. A person can encourage the fetus to roll into the ideal position by leaning in the direction in which they want the fetus to move.
This involves the fetus lying horizontally. Most do not remain in this position in the weeks and days leading up to labor.
If a fetus is still in this position just before birth, a cesarean delivery will be necessary.
Otherwise, there is a risk of a medical emergency known called umbilical cord prolapse. It involves the umbilical cord entering the birth canal before the baby.
The breech position involves the fetus resting with the head up instead of down in the pregnant person’s pelvis. Some different types of breech position include:
- Frank breech: The fetus’s legs are straight up in front of the body, so the feet are near the face.
- Complete breech: The fetus “sits” with the legs crossed in front of the body, so the feet are near the buttocks.
- Footling breech: One or both feet hang below the fetus’s bottom. If the birth is vaginal, one or both feet emerge first.
Some reasons why a fetus may remain in a breech position include:
- too much or too little amniotic fluid
- uterine fibroids
- an irregularly shaped uterus
- multiple fetuses
In the case of twins, one fetus may be in an anterior or posterior position while the other is in a breech position.
It is safe for a fetus to be in any of the above breech positions during the pregnancy. But when labor begins, there are some risks if the baby is still in a breech position.
Around 3–4% of fetuses are in breech position by the time of delivery.
The best way to find out is to speak with the doctor or midwife.
At each appointment during the second and third trimesters, the doctor or midwife should feel the person’s abdomen to check the position of the fetus.
At the 35–36 week appointment, they check whether the fetus has moved into an anterior or posterior position. If the healthcare professional is unsure after a physical examination, they may request an ultrasound scan.
It may also be possible for a person to tell which position their developing baby is in.
When the fetus is in the back-to-back, or posterior, position, the pregnancy bump may feel squishy. The person may also feel kicks around the middle of their belly, and some see an indentation around their belly button.
When the fetus is in the anterior position, the person may feel more kicks under the ribs, and their belly button may “pop out.”
Belly mapping is a concept created by Spinning Babies. A person can use it to check the position of the fetus.
Some factors that can help include:
- any information from a recent scan or hospital visit
- knowing where the placenta is
- knowing how much amniotic fluid there is
- having well-toned abdominal muscles
- choosing a time when the fetus is active
- being aware of fetal movements over the last few days
A person can map the position by drawing on a piece of paper or on their belly with a nontoxic marker.
To do belly mapping:
- Find a time and place where you can fully or partially lie down for around 15 minutes, with your belly tilted to one side.
- Relax and breathe deeply.
- Apply gentle pressure with the fingertips to the area around the top of the pelvis or pubic bone. If you feel something hard, it is likely the head. If the area is soft, it is likely the fetus’s bottom. Mark this as a circle on your belly or the paper.
- Next, feel around your abdomen for a long, smooth shape, which is likely the back. It may be on one side or another. Mark it as a curved line on your map. If you can only feel soft shapes or limbs, the baby is probably facing forward.
- Be aware of any kicks or movements and mark them as dots or waves.
- By adding color and other features, you can turn your image into a picture to keep.
Most fetuses adopt a head-down position by delivery. If a fetus is in a breech position at 36 weeks , a doctor or midwife may suggest an external cephalic version (ECV).
This procedure involves the doctor or midwife trying to turn the fetus manually.
First, they give the pregnant person an injected drug that relaxes their uterus. Then, placing their hands on the outside of the person’s belly, the doctor or midwife gently manipulates the fetus from a breech position into a transverse lie position, then into a head-down position.
An ECV does not always work, but it is effective in around 58% of cases.
Also, some fetuses turn by themselves after 36 weeks, and some even turn during labor.
Anecdotal reports suggest that moving into certain positions, taking herbal medicines, and doing particular exercises may help babies in breech adopt a more favorable birthing position. But there is no reliable evidence that any of these methods work.
If a person wants to try these medicines or techniques, it is vital to consult a doctor first.
Below are answers to common questions about fetal positions during pregnancy.
How can you tell how your baby is positioned in the womb?
A hospital scan can show you, but you can also try belly mapping. This involves taking time to relax and feeling for the head, bottom, back, and limbs, and noticing any movements.
What does it mean if the baby is on the left side?
If the fetus is on the left side of the uterus, doctors call this the left occiput anterior position. Some people have traditionally considered this to be the best position at the start of labor, but a 2013 study found no evidence to confirm it.
What is a “normal” position for a baby?
A fetus changes position many times as it develops, but the most common and most helpful position at the time of delivery is the occiput anterior position, in which the head is down, the chin is tucked in, and the fetus is facing the pregnant person’s back.
A fetus moves into many positions throughout pregnancy. During the last few weeks, most move into an anterior position, which is the most helpful position for a vaginal birth.
If a fetus is still in a transverse lie or breech position just before labor, the doctor or midwife takes steps to ensure the safety of the person and the baby during birth.
- Fertility
- Pregnancy / Obstetrics
- Women’s Health / Gynecology
- Parenthood
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- Ahmad, A., et al. (2013). Association between fetal position at onset of labor and mode of delivery: A prospective cohort study.
https://obgyn.onlinelibrary.wiley.com/doi/full/10.1002/uog.13189 - Baby positions in the womb before birth. (n.d.).
https://www.nct.org.uk/birth/baby-positions-birth - Breech babies: What you need to know. (n.d.).
https://www.nct.org.uk/labour-birth/different-types-birth/assisted-or-complicated-birth/breech-babies-what-you-need-know - Getting your baby into the best birth position. (2016).
https://www.tommys.org/pregnancy/labour-birth/baby-best-position-birth - Guittier, M.-J., et al. (2014). Maternal positioning to correct occipito-posterior fetal position in labour: A randomised controlled trial.
https://bmcpregnancychildbirth.biomedcentral.com/articles/10.1186/1471-2393-14-83 - If your baby is breech. (2019).
https://www.acog.org/Patients/FAQs/If-Your-Baby-Is-Breech - Multiple pregnancy. (2020).
https://www.acog.org/Patients/FAQs/Multiple-Pregnancy - Shanahan, M. M., et al. (2021). External cephalic version.
https://www.ncbi.nlm.nih.gov/books/NBK482475/
Third Trimester Ultrasound Pictures
Take a sneak peak at your baby’s development with this slideshow of ultrasound pictures from the third trimester of pregnancy.
Updated on June 26, 2023
While most expecting parents would love to get a look at their baby-to-be on a weekly (or daily) basis, it’s customary to only receive one or two ultrasounds during pregnancy. Luckily, looking at ultrasound images of other babies, say at 30-week or 34-week ultrasounds, can still give you a very close approximation of what your baby looks like and what’s happening with their growth and development.
Enter our slideshow of the third trimester of pregnancy, made in conjunction with the American Institute of Ultrasound Medicine (AIUM), Johns Hopkins, and the March of Dimes. This array of images gives you a look at each week of development to reveal all the intricate details of your baby’s growth—until you get to meet them in person.
28 Week Ultrasound
American Institute of Ultrasound in Medicine – AIUM.org
Fetal Size: Length, 10 inches, crown to rump; total length 15 3/4 inches. Weight, almost 2 1/2 pounds
Fetal Development Milestones: Your baby now has added brain tissue and their scalp hair is continuing to grow. Their eyes are opening and they’re gaining weight.
What You’re Seeing: Your baby-to-be’s hair is seen waving in the amniotic fluid. This hair is called lanugo. Unfortunately, we can’t predict how much hair your baby will have because he will lose his lanugo before being born and it will be replaced with the hair we’re used to seeing on infants at birth.
29 Week Ultrasound
American Institute of Ultrasound in Medicine – AIUM.org
Fetal Size: Length, 10 1/2 inches, crown to rump; total length 16 3/4 inches. Weight, 2 3/4 pounds
Fetal Development Milestones: Your little one’s muscles are maturing. They’ll continue to gain weight over the coming weeks.
What You’re Seeing: At 29 weeks, your baby-to-be’s bones are hardening, and they’re muscles strengthening. In fact, you may have noticed from their kicks and jabs that they’re growing stronger each week. Bones appear bright white on a sonogram. Although you can’t see it in this image, your baby has probably been practicing their breathing movements this week, though their lungs still need more time to mature.
30 Week Ultrasound
American Institute of Ultrasound in Medicine – AIUM.org
Fetal Size: Length, 10 3/4 inches, crown to rump; total length 17 inches. Weight, 3 pounds
Fetal Development Milestones: At a 30-week ultrasound, it’s clear that the baby’s eyes are opening and they’re gaining weight.
What You’re Seeing: This image shows how developed your baby-to-be’s features have become. With their pouty lips and tiny nose, they look a lot like they will at birth. Note the baby’s hand in front of their eyes and forehead.
Sleep Cycles: Weeks 26 to 30 of Pregnancy
31 Week Ultrasound
American Institute of Ultrasound in Medicine – AIUM.org
Fetal Size: Length, 11 3/4 inches, crown to rump; total length almost 18 inches. Weight, 3 1/2 pounds
Fetal Development Milestones: At 31 weeks, your baby continues to develop as they gain weight.
What You’re Seeing: This image gives a close-up view of the lower end of your unborn baby’s spine. You can see the spinal cord protected by the bright white bones of the spine.
32 Week Ultrasound
American Institute of Ultrasound in Medicine – AIUM.org
Fetal Size: Length, 11 1/2 inches, crown to rump; total length 19 inches. Weight, 4 pounds
Fetal Development Milestones: Baby’s toenails are now formed, they’re practicing their breathing, and they’re continuing to gain weight and grow.
What You’re Seeing: There’s not much to report on your baby-to-be’s developmental milestones this week. Much of their growth is strictly adding weight through fat layers that will insulate their maturing organs. They’ll need plenty of fat tissue to keep them warm once he leaves their home in your womb and enters the world, where the environmental temperature is not as controlled.
Although you can’t see it in this image, your baby has probably been attempting to breathe this week, though his lungs still need more time to mature. Another development you’ll notice in this image—look closely and you might spy the edges of his toenails, which are now fully formed.
33 Week Ultrasound
American Institute of Ultrasound in Medicine – AIUM.org
Fetal Size: Length, 12 inches, crown to rump; total length 19 1/2 inches. Weight, 4 1/2 pounds
Fetal Development Milestones: Your baby is getting more plump each day.
What You’re Seeing: Your baby-to-be’s brain is continuing to grow and develop. In this image, the red and blue show blood flow to the part of his brain that lets the two halves of the brain communicate with one another.
34 Week Ultrasound
American Institute of Ultrasound in Medicine – AIUM.org
Fetal Size: Length, 12 3/4 inches, crown to rump; total length 19 3/4 inches. Weight, 5 pounds
Fetal Development Milestones: Baby’s lungs are continuing to mature and they’re continuing to gain weight.
What You’re Seeing: In this image of a profile, the baby’s mouth is open. They may be drinking amniotic fluid or taking it into their lungs, which aids in the development of their respiratory system.
Growing Big: Weeks 31 to 34 of Pregnancy
35 Week Ultrasound
American Institute of Ultrasound in Medicine – AIUM.org
Fetal Size: Length, 13 1/4 inches, crown to rump; total length 20 1/4 inches. Weight, 5 1/4 pounds
Fetal Development Milestones: The baby’s kidneys are fully developed and their liver is functioning. They continue to add weight each week.
What You’re Seeing: This closeup shot of your baby-to-be’s ear shows how fully developed their facial features have become. They now look like the newborn that you’ll be welcoming into the world in a few weeks (only five more to go!). Your baby is also maturing on the inside too. They continue to practice their breathing movements, which move amniotic fluid in and out of their lungs to aid in their development.
36 Week Ultrasound
American Institute of Ultrasound in Medicine – AIUM.org
Fetal Size: Length, 13 1/2 inches, crown to rump; total length 20 3/4 inches. Weight, 6 pounds
Fetal Development Milestones: Not much new to report at 36 weeks! Your baby continues to gain weight.
What You’re Seeing: This image of your baby-to-be’s face looks identical to the profile you’ll be seeing in person in a few weeks (four or less!). For the remaining weeks, your baby will be adding 1/2 pound each week until birth.
37 Week Ultrasound
American Institute of Ultrasound in Medicine – AIUM.org
Fetal Size: Length, 14 inches, crown to rump; total length 21 inches. Weight, 6 1/2 pounds
Fetal Development Milestones: At 37 weeks, our baby is officially full-term!
What You’re Seeing: Sometimes, your doctor or midwife will ask for a test to check how well your baby is doing. One indicator of your baby-to-be’s well-being is a measurement of the amniotic fluid. This can also be part of a test called a biophysical profile, which will also include watching the baby’s various movements.
In this image, the sonographer is measuring the deepest pocket of fluid in each of the four areas of your uterus. As you can see, your baby is getting a bit crowded in there!
38 Week Ultrasound
American Institute of Ultrasound in Medicine – AIUM.org
Fetal Size: Length, 14 inches, crown to rump; total length 21 inches. Weight, 6 3/4 pounds
Fetal Development Milestones: All of your baby’s major body systems are working, and they’re continuing to practice breathing in utero. Their movements will lessen as they run out of space.
What You’re Seeing: During the last few weeks of gestation, your baby has less and less room to move. A few weeks (and pounds) ago, they may have been kicking and wiggling constantly; now they simply don’t have enough room.
If you or your healthcare provider have any concerns about your baby’s development, especially if their movement becomes too infrequent, you may have an ultrasound to check up on them. This image shows the results of monitoring a baby’s heart rate in utero. At the top, the baby’s heart beats; below, the lined measurements track and then determine the baby’s heart rate to make sure it’s within the normal range.
39 Week Ultrasound
American Institute of Ultrasound in Medicine – AIUM.org
Fetal Size: Length, 14 1/2 inches, crown to rump; total length 21 1/2 inches. Weight, around 7 pounds
Fetal Development Milestones: At 39 weeks, your delivery day is coming soon!
What You’re Seeing: What you’re seeing: The sonographer is getting a 3/4 view of your baby-to-be’s face, and you can actually see their eyelashes! Your medical provider may want to see if the baby has settled into a breech position or head-down position, which is the ideal position for normal delivery.
40 Week Ultrasound
American Institute of Ultrasound in Medicine – AIUM.org
Fetal Size: Length, 14 3/4 to 15 1/4 inches; total length 21 1/2 inches. Weight, 7 1/2 pounds
Fetal Development Milestones: Delivery day!
What You’re Seeing: If your healthcare provider wants to get an idea of your baby’s weight, one of the most important measurements the sonographer can take is abdominal circumference. This image is a cross-section of your baby’s belly. The small back oval of their stomach, and the curved black line is the blood vessel that brings nutrients from the placenta. Soon, you’ll have a very different way of feeding your baby!
