Fetal Positions

What are the common birth position called, and how are they characterized?

Common birth positions refer to the different ways a baby can be positioned in the uterus or birth canal before or during labor. These positions are typically described in relation to the mother’s pelvis. The most common birth positions include:

1. Vertex (or cephalic) presentation: This is the most common birth position, where the baby’s head is down and the baby is facing the mother’s back. In a vertex presentation, the baby is positioned to be born headfirst, which is considered the optimal position for a vaginal birth.
2. Occiput anterior: In this position, the baby’s head is down and facing towards the mother’s back. This is also considered an optimal position for a vaginal birth, as the baby’s head is able to pass through the pelvis more easily.
3. Occiput posterior: In this position, the baby’s head is down, but facing towards the mother’s front. This position is also known as “sunny-side up” and can sometimes make labor longer and more difficult.
4. Breech presentation: In a breech presentation, the baby’s buttocks or feet are positioned to be born first, rather than the head. Breech presentations can increase the risk of complications during birth and may require a cesarean section delivery.
5. Transverse presentation: In a transverse presentation, the baby is positioned sideways in the uterus, rather than head-down or feet-first. Transverse presentations are rare and almost always require a cesarean section delivery.

The specific birth position of the baby can be determined through a physical exam or ultrasound during pregnancy. Understanding the baby’s position can help healthcare providers plan for a safe and successful delivery.

When should my baby move into position for birth?

Most babies will move into the head-down position, known as the vertex position, by the time labor begins. This typically occurs between the 32nd and 36th weeks of pregnancy. However, some babies may not move into the head-down position until later in pregnancy or even during labor.

If your baby has not moved into the head-down position by around 36 weeks, your healthcare provider may monitor the baby’s position more closely. In some cases, techniques such as external cephalic version (ECV) may be used to try to gently move the baby into the head-down position. If these methods are unsuccessful or if there are other factors that make a vaginal birth less likely to be successful, a cesarean section delivery may be recommended.

It’s important to discuss your baby’s position with your healthcare provider if you have any concerns. They can provide guidance on monitoring the baby’s position and making a plan for a safe delivery.

What is external cephalic version?

External cephalic version (ECV) is a procedure used to try to turn a baby from a breech position (feet or buttocks first) to a head-down position before labor begins. The procedure is usually performed around 37 weeks of pregnancy, when there is still enough amniotic fluid to allow the baby to move, but before the baby has descended into the pelvis, making it harder to turn.

During an ECV, healthcare providers use their hands on the outside of the mother’s abdomen to gently push and manipulate the baby into a head-down position. The procedure is typically done in a hospital setting, where the baby’s heart rate can be monitored closely.

ECV is not always successful, and there are risks involved, including placental abruption (when the placenta separates from the uterus), umbilical cord compression, and fetal distress. However, for women who prefer a vaginal birth or want to avoid a cesarean section, ECV can be an option to consider after discussing the risks and benefits with their healthcare provider.