In approximately 96 percent of all births, the fetus assumes a head-down position around the 36th week of pregnancy, and the baby is born head first. In some cases, however, the fetus fails to assume this position, and when labor begins the baby is still in a feet-down or bottom-down position. This is called breech birth, and it creates a potentially dangerous situation for both mother and baby.
Categories of Breech Birth
There are three distinct categories of breech birth:
- Frank breech: The baby is positioned so that his or her bottom will exit the birth canal first. The legs are pointed toward the head, and the knees are extended, so that the feet are near the ears. This position accounts for 65–70 percent of breech births.
- Complete breech: The baby sits crosslegged, with the feet near his or her bottom.
- Footling breech: one or both legs are extended so that feet come first. This is rare for full-term babies, but more common in cases of premature birth.
Other malpresentations—i.e., difficult positions a fetus can assume—include:
- Transverse position (also known as the oblique or shoulder position): the baby is sideways, with its spine perpendicular to the mother’s.
- Face Presentation: the baby comes out face first. If the baby’s chin is at the top, it can be delivered vaginally. If the chin is down, a C-section is required.
- Compound: an arm or leg enters the birth canal along with the head.
Risks of Breech Birth
In the United States and Canada, most breech babies are delivered via C-section, and most American hospitals have policies in place that forbid vaginal breech births. In an effort to reduce C-section rates, there has been discussion about ways to encourage attempts at external cephalic version, also known as ECV. ECV is a non-invasive method of turning a baby around, which we will discuss later in this article.
If your baby is discovered to be in a breech position and a C-section delivery is planned, it will usually not be scheduled before the 39th week of pregnancy. If you go into labor before your planned C-section, it is very important that you go as quickly as possible to the emergency room as soon as your water breaks. This is a medical emergency, and you need to treat it as such.
In the normal, head-down position, a baby’s skull compresses in a certain way in order to fit through the birth canal; this process is called molding. But if the baby comes out feet first, its body does not stretch the birth canal wide enough for the head to pass through easily. The head can become stuck in the birth canal, which prolongs labor and causes fetal distress.
Another risk of vaginal breech delivery is umbilical cord prolapse. This is when the umbilical cord passes through the cervix and enters the birth canal before the baby does. This is a dangerous situation, as the cord can become pinched, depriving the baby of oxygen. The baby must be delivered as quickly as possible if this happens; the infant mortality rate under these circumstances is 11 to 17 percent.
These factors influence the safety of vaginal breech birth:
- Category of breech birth—favorable outcomes are more common with babies in the frank breech position
- Size of baby in relation to size of mother’s pelvis
- Birth order of twins: If the first of a pair of twins is born head-down, a safe vaginal breech delivery of the second is more likely.
- The number of babies the mother has previously delivered
Causes of Breech Birth
While the causes of breech positioning are not well understood, certain conditions are known to make breech birth more likely:
- Too little amniotic fluid in the womb
- Multiple fetuses in the womb
- Premature birth, especially before the 37th week
- Long umbilical cord
- The size or shape of the uterus
- Abnormal growths in the uterus, e.g., fibroids
- Previous pregnancy
- Placenta previa
Diagnosing Breech Birth
It is not always easy to determine the position of a baby in the womb, and you may be near the end of your pregnancy before it is possible to tell whether you have a breech baby. Your doctor will examine you manually to feel for the position of the baby’s head, and you will be given an ultrasound.
Prognosis for Breech Birth
If your baby is in a breech position, your doctor may attempt to turn it around by using a technique known as external cephalic version (or ECV). This involves the doctor placing his or her hands on the mother’s abdomen and pushing or lifting in an attempt to roll the baby around so that its head is in the correct position. An ultrasound is administered at the same time in order to enable the doctor to see what he or she is doing. In some cases the mother is given a medication that relaxes the uterus in order to ease the version process. ECV is usually not attempted before the 36th week of pregnancy because of the possibility that the baby might turn around and reassume the breech position. This sometimes happens anyway, but more than 50 percent of ECV procedures are successful. It is never advised that you try this yourself!
While vaginal delivery of breech babies is sometimes possible, your doctor may still recommend a C-section delivery in the event of an umbilical cord prolapse, or if the labor is progressing abnormally in some other way.
Talking to Your Doctor
Here are some questions you can ask your doctor about breech birth.
- Is my baby in the correct position?
- If my baby is not in the correct, head-down position, is it possible that you will be able to turn it around before my due date?
- Will a C-section be necessary?
- I would prefer a traditional vaginal birth, if possible; what are the chances I will be able to have one?
- Is my baby’s life in danger?
- Is my baby at risk for any birth defects?