During pregnancy, the developing baby moves into several different positions. As labor approaches, some positions are safer than others.
The ideal position for a fetus just before labor is the anterior position. In this position, the fetus's head points toward the ground and they are facing the woman's back.
Most fetuses settle into this position by the last month of pregnancy. The anterior position is also known as a vertex, cephalic, or occiput anterior position.
The anterior position may reduce the chances of complications during pregnancy. Learn more about this and other fetal positions in the womb in this article.
Possible positions of a developing baby in the womb include:
The best position for the fetus to be in before childbirth is the anterior position. The majority of fetuses get into this position before labor begins.
This position means the fetus's head is down in the pelvis, facing the woman's back. The fetus's back will be facing the woman's belly.
This position means the fetus's head can be tucked in, allowing the top of it to press down on the cervix, which encourages it to open during labor.
A doctor or midwife may describe a fetus that lies slightly to the left as left occiput anterior or LOA, and one that lies slightly to the right as right occiput anterior or ROA.
The posterior position is also known as the back-to-back position. This is where the fetus's head is pointing down, and their back is resting against the woman's back.
In this position, it can be difficult for the fetus to tuck their head in, which can make passing through the smallest part of the pelvis more challenging. This can lead to a slower and longer labor than the anterior position, and may also cause a backache.
A fetus may be more likely to end up in this position if the mother spends a long time sitting or laying down, such as if she is on bed rest.
The back of a fetus's body is heavier than the front, so a pregnant woman can encourage the fetus to roll into the ideal position by leaning in the direction they want them to move.
Transverse lie position
A transverse lie position is when the fetus is lying horizontally in the uterus. Most fetuses will not remain in this position in the weeks and days leading up to labor.
If a fetus is still in the transverse lie position just before birth, a cesarean delivery will be necessary.
Without a cesarean delivery, there is a risk of a medical emergency known as an umbilical cord prolapse.
When an umbilical cord prolapse occurs, the woman delivers the umbilical cord in the birth canal before the baby.
The breech position is when the fetus remains with the head up instead of down in the woman's pelvis. There are different types of breech position, including:
- Frank breech: In this position, the fetus's legs lie straight upward in front of their body, so the feet are near the face.
- Complete breech: In this position, the fetus "sits" with their legs crossed in front of the body, so the feet are near their buttocks.
- Footling breech: In this position, the fetus has either one or both feet hanging below their bottom. If a woman gave birth vaginally, one or both feet would come out first.
Reasons why a fetus may remain in the breech position include:
- too much or too little amniotic fluid surrounding the fetus
- uterine fibroids
- an irregularly shaped uterus
- multiple fetuses in the womb
If a woman is carrying twins, one fetus may be in an anterior or posterior position while the other fetus is in a breech position.
It is safe for a fetus to be in any of the above breech positions while they are in the womb. However, there are some risks if the fetus is still in a breech position when labor begins.
The best way of finding out which position the fetus is in is by talking to a doctor or midwife.
At each appointment during the second and third trimesters of pregnancy, a doctor or midwife should feel the woman's abdomen to check the position of the fetus.
At the 35–36 week appointment, they will check to ensure that the fetus has moved into an anterior or posterior position. If the doctor is unsure about whether the fetus is in the correct position after a physical examination, they may request an ultrasound scan.
It may also be possible for the woman to tell which position the fetus is in at home.
When the fetus is in the back-to-back or posterior position, the pregnancy bump may feel squishy. A woman may also notice kicks around the middle of the belly, and some people may also see an indentation around their belly button.
When the fetus is in the anterior position, a woman may feel more kicks under the ribs. Their belly button may also "pop out."
Most fetuses turn into the head-down position by 36 weeks. If a fetus is in a breech position at 36 weeks, a doctor or midwife may suggest an external cephalic version (ECV).
An ECV is a procedure where a doctor or midwife will try to turn the fetus manually.
For this procedure, they will first insert a small needle into the woman's hand to relax the uterus.
Using their hands on the outside of the pregnant woman's belly, a doctor or midwife will then gently manipulate the fetus from a breech position into a transverse lie position, then into a head-down position.
Some fetuses turn by themselves after 36 weeks, and some even turn during labor.
Some people recommend moving into certain positions, taking herbal medicines, and doing particular exercises to help babies in breech turn to the more favorable birthing position. However, there is no reliable evidence to prove that any of these methods work.
If a person does wish to try these medicines or techniques, it is vital to consult a doctor first.
A baby will move into many different positions throughout pregnancy. During the last few weeks of pregnancy, most babies move into an anterior position, which is the best position for vaginal birth.
If a baby is still in a transverse lie or breech position just before labor, a doctor or midwife will make medical interventions to ensure the safety of the woman and baby during childbirth.