Fetal Position

When the baby is laying with the head down towards the vagina that is called vertex presentation. This is the position that is the safest for a normal vaginal delivery. When the baby is laying with its head up towards the mom’s chest and the bottom down towards the vagina that is called breech. When the baby is laying sideways that is called transverse. A transverse baby can not delivery vaginally, it just won’t fit that way. Most people feel that a breech delivery is very dangerous and the risk is not justifiable. At least in the United States, breech babies are generally delivered by c-section.

The head is generally the biggest part of the baby. Once the head delivers there will be room for the rest of the baby. In a breech delivery it is possible to deliver the bottom and the shoulders but for the head to get stuck. This is called a “hung head” and the baby can die. This potential disaster is why breech deliveries are frowned upon in the USA.

Because of the way the bony structure of the pelvis, the soft tissues of the pelvis, and the uterus are constructed, babies generally fit best head down (vertex). Due to this spatial best fit, once a baby near term finds its way head down it is unlikely to change positions. The baby fits best head down and has more room and more comfort that way. Breech transverse babies usually end up head down by delivery. It is estimated that 95% of babies that are breech at 32 weeks will be vertex by term. If you find out your baby is breech in the early 3rd trimester, don’t let anyone talk you into doing something that will turn the baby, it will do it by itself. There are people that will provide some expensive treatment for a pregnant woman with a breech baby at 32 weeks and guarantee that the baby will be vertex by delivery or your money back. Since 95% of babies will turn on their own, this is a rip off!

The doctor will want to determine if the baby is head down at 35-36 weeks. This is usually done with an internal exam (the doctor’s gloved fingers in the vagina) with the group B strep test. If it is uncertain, an ultrasound can be performed to find the position. At this point if the baby is breech it is less likely, though still possible, that it will turn on its own. A version can be performed at 37 weeks. A version is a procedure where the doctor will push on the women’s abdomen in an attempt to turn the baby. Transverse babies tend to turn fairly easily. Breech babies can be more difficult with a success rate of about 50%. There are many factors to help predict the safety and chance of success of a version. Your doctor will likely do an ultrasound to look at the exact position of the baby, check the amount of amniotic fluid, check for a nuchal cord, as well as other predictors of safety and success. The risk of a version is an abruption where the placenta can get bruised. Depending on the degree of bruising this can be a significant problem and may necessitate an emergency c-section. This complication is rare but can occur.

There are many interesting suggestions about how to encourage a baby to move head down. I have had patients use music to try to coax the baby head down. Bags of frozen peas to help guide the baby have been tried. Different positions for a woman to spend time in is often advocated. There is limited data on all of these techniques. If they are not dangerous or uncomfortable it is certainly safe to try.