Babies are ordinarily born headfirst, which is known as vertex presentation. They may float around freely in the uterus during the early and middle months of pregnancy, but most move into the head-down position by about the 37th week. If by week 37 your baby is in a feetfirst or buttocks-first position, it is called a breech presentation. Breech presentation occurs in about 3 percent of full-term births.
Risks of a breech birth. Doctors prefer not to deliver breech babies vaginally because they are more likely than vertex babies to suffer from complications during delivery. The baby's feet and umbilical cord can get tangled. Very rarely, the slim body comes out but the head gets stuck. These complications are rare, but your doctor must act quickly to avoid problems for the baby.
When version may be used. If at week 37 your doctor suspects that your baby is breech, she may send you for an ultrasound to find out for sure. If the ultrasound confirms the diagnosis, your doctor may recommend a version (also called an external cephalic version), which is the manual turning of the baby into the head-down position. Your doctor may offer to do the version that day or within a couple of days, but she won't wait long because within a week or two the baby's bottom may be so low in the pelvis that a version will not work.
A version may start with an intravenous shot of a uterus-relaxing drug for you and a nonstress test or biophysical profile for your baby. If your baby is moving normally, the version will begin. Using ultrasound to guide her and to monitor the health of your baby, the doctor places her hands on your abdomen and applies pressure, pushing the baby's bottom up and guiding the head to encourage a somersault. She is literally trying to turn the baby upside down. After the version, your doctor will do another nonstress test or biophysical profile to ensure that your baby tolerated the move.
Having a version can be uncomfortable. Because it carries a very small risk of placental abruption, premature rupture of the membranes, tangling of the cord, or starting labor, it should be done in a hospital where an emergency cesarean can be performed.
If the version is successful, your baby will move from breech to vertex. The procedure works about half the time; the success rate is higher if a woman has had a baby before. Most babies then stay in the head-down position, but some move back into breech. Your doctor's goal is to get your baby head-down and keep her there because your chances of having an uncomplicated vaginal birth are much higher with a head-down baby. Although breech babies are sometimes delivered vaginally, most are born by cesarean delivery.
A version is not recommended for women who have any of the following complications: vaginal bleeding, a placenta that is covering the opening of the uterus, an abnormally small baby, a low level of amniotic fluid, an abnormal fetal heart rate, premature rupture of the membranes, or more than one baby.
Originally published in You & Your Baby: Pregnancy.
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