Babies have two basic options at birth: They can come out the hard way, or the really, really hard way. Ninety-seven percent of babies enter the birth canal headfirst, the safest approach for both mother and baby. The other 3 percent enter feet-first, bottom-first, or a combination of both. This is called a breech presentation.
There are three different types of breech presentations. Some breech babies enter bottom-first with their legs extended and their feet near their head. This is called a "frank breech," and it's the most common breech position. Babies in the frank breech position can sometimes be born vaginally, but only in special circumstances. If the baby is too large, if the birth canal is too narrow, or if the baby starts showing signs of distress during labor, a cesarean section will be necessary.
If your doctor does attempt a vaginal delivery, its best to have an experienced practitioner who has quick access to the tools he needs for an emergency cesarean section. That means this should not be attempted outside a hospital or in a small hospital where emergency c-sections cannot be performed immediately when necessary.
A complete breech occurs when a baby enters bottom-first with his legs folded. A baby who enters the birth canal feet-first is in the footling breech position. If your baby is in either of these positions when you go into labor, experts say, you will need a cesarean section: A vaginal birth would be too risky.
Why are vaginal breech deliveries dangerous?
When a baby is born headfirst, his head molds to the shape of the birth canal. That's why many babies are born with slightly pointed heads. But when a baby is in breech position, his head doesn't have a chance to slim down. If the head can't be delivered quickly enough, the baby could suffocate. Also, the umbilical cord may get squeezed during a breech delivery, potentially cutting off a baby's oxygen supply.
If a baby is on the large side, he may not be able to go backwards through the birth canal no matter how hard his mom pushes. Surprisingly, small babies can have just as much trouble. When a breech baby weighs less than five pounds, the mother's cervix may not open enough for delivery. The head may be disproportionately large in relation to the body, and it might get stuck as it passes through the birth canal.
Can breech deliveries be prevented?
Your doctor will check your baby's position at every visit in the third trimester, and pay special attention to it a few weeks before your due date. If your baby is in a breech position, your doctor may try turning him around by pushing strategically on your belly.
This procedure is called external version, or just version, and it is usually done in a hospital setting where the baby's heart rate can be carefully monitored and where a c-section can be performed if anything goes wrong with the procedure (rare complications can include premature rupture of membranes and preterm labor). Version is typically tried in cases where the baby is in breech position after 36 or 37 weeks gestation.
If you or your doctor decide against this procedure -- or if it doesn't work -- you may be asked to try some special exercises. However, there's not much evidence of success for alternative approaches to turn a breech baby. Although the approaches may be worth trying, many doctors believe that version with an experienced physician under careful monitoring is the safest option. If version succeeds in turning the baby, you can still have a vaginal birth.
If your baby is still in the breech position as the due date approaches, you should discuss delivery options with your doctor. Your baby may be uncooperative, but he still deserves the safest start to life.
American Pregnancy Association. Breech presentation. February 2005. http://www.americanpregnancy.org/labornbirth/breechpresentation.html
American Academy of Family Physicians. Breech babies: What can I do if my baby is breech? September 2004.
Curtis, Glade MD and Judith Schuler. Your Pregnancy Week by Week. 5th edition. 2004 Da Capo Press.
The Merck Manual, Second Home Edition. Fetus or Newborn Problems. http://www.merck.com/mmhe/print/sec22/ch261/ch261c.html
The Mayo Clinic. Fetal Positions. August 8 2009 http://www.mayoclinic.com/health/fetal-positions/PR00080
Coco AS, et al. External cephalic version. American Family Physician. Vol. 58/No. 3, September 1, 1998.