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What’s the truth about vaginal birth after cesarean section?

What have you heard about vaginal birth after a cesarean section (VBAC)? That your uterus might rupture if you try it? That you’re likely to endure the pain of labor only to end up with another surgical delivery?

While uterine rupture is the most serious risk associated with VBAC, it occurs in less than 1 percent of cases. As for the second rumor, it’s certainly possible that you may have a second cesarean section following a trial of labor. But it’s worth noting that up to four out of five women who try VBAC have successful vaginal deliveries.

Although no one has come up with a way to determine ahead of time which mothers will be able to deliver vaginally after a C-section, it is known that the success rate varies depending on the reason for the previous C-section. For example, women whose previous cesarean was done because the baby was breech (positioned so that buttocks or feet would be first out of the birth canal) or because the baby was thought to be in distress have higher success rates. Women who had a cesarean because of cephalopelvic disproportion (where the baby’s head is too big to fit through the mother’s pelvis) or failure to progress (where labor has stalled or the baby isn’t advancing) are slightly less likely to avoid a C-section, but even they are successful about two-thirds of the time.

Despite the low risk and high chance of success, many women still schedule a C-section rather than try labor. Why should you consider VBAC? For two reasons:

  1. It’s safer. Studies comparing the outcomes of VBAC to cesarean section show that women who have VBAC deliveries are less likely to suffer complications, such as fever (a sign of infection) and increased blood loss (which may require a postpartum transfusion). Although fewer than one in 10,000 women die in childbirth each year in the U.S., those who do die are more likely to have had a surgical delivery than a vaginal delivery.
  2. The recovery is shorter from a vaginal delivery. Women who have VBAC deliveries leave the hospital sooner and recover faster than those who have C-sections. The downside of a longer recovery associated with surgical birth: You may not be able to care for your newborn as actively as you’d like.

There’s one group of women for whom VBAC is clearly contraindicated: Those whose first cesarean was done using a classical vertical uterine incision that extends to the top of the uterus. A classical incision doesn’t heal as strongly as an incision that’s transverse (from side to side). However, a low vertical incision—an up-and-down cut made in the lower part of the uterus—does allow for an attempted VBAC.

It’s important to note that the scar on your belly isn’t necessarily an indication of which type of incision you had in your uterus, so your doctor should consult the medical records from your first delivery.

There has been a great deal of debate about whether VBAC is too risky to be routinely recommended for women who have had two or more previous C-sections and for women whose babies are breech or are estimated to weigh more than 8 3/4 pounds. The safety of VBAC for women carrying more than one fetus has also been questioned.

According to the latest VBAC guidelines published by the American College of Obstetricians and Gynecologists, there isn’t enough evidence to indicate whether those factors increase the risk of uterine rupture associated with VBAC. The guidelines do conclude that nondiabetic women carrying babies with an estimated weight greater than 8 3/4 pounds should not be disqualified from a trial of labor. If you’re debating VBAC, talk to your doctor. He or she will help you reach a decision.