Vaginal Birth after Cesarean (VBAC)

Reviewed by George Mussalli, M.D. and Ann Linden, CNMMarch 2005
By the BabyCenter editorial staff

What are my chances of giving birth vaginally after having a c-section?
As long as you're an appropriate candidate for a vaginal birth after a cesarean, also known as a VBAC, there's a good chance you'll succeed. Of course, your chances of success are higher if the reason for your c-section isn't likely to be an issue this time around. For example, if you had a c-section after being fully dilated and pushing for three hours with a small baby who was properly positioned, you're much less likely to have a successful VBAC than a woman who has already had an easy vaginal delivery and then had a c-section when her next baby was breech. (Having given birth vaginally before boosts your odds dramatically.) Overall, about 60 to 80 percent of women who attempt a VBAC succeed.If you decide to try it, you'll need a caregiver who supports the idea and has admitting privileges at a hospital where appropriate coverage is available around-the-clock and whose policies allow VBACs. An increasing number of hospitals are refusing to allow VBACs because of controversy about their safety, specifically the potential for uterine rupture (a rare injury, but one that can be catastrophic for mother and baby).

What would make me a good candidate for a VBAC?
According to the American College of Obstetricians and Gynecologists, you're a good candidate for a vaginal birth after a c-section if you meet all of the following criteria:
• You've had only one previous cesarean delivery and it was done with a low-transverse (horizontal) incision. Having had more than one c-section or an incision in your upper uterus that was vertical (also known as "classical") or T-shaped puts you at an increased risk for uterine rupture. Note that the type of scar you have on your belly may not match the one on your uterus, so your practitioner will need to review a copy of your c-section report.

• Your pelvis seems large enough to allow your baby to safely pass through. (While there's no way to know this for sure, your practitioner can examine your pelvis and make an educated guess.)

• You've never had any other uterine surgery, such as a myomectomy to remove fibroids.

• You've never had a uterine rupture.

• You have no medical condition or obstetric problem that would make a vaginal delivery risky.

• There's a physician on site who can monitor your labor and perform an emergency c-section if necessary.

• There's an anesthesiologist, other medical personnel, and equipment available around-the-clock to handle an emergency situation for you or your baby.VBACs are very controversial, and you may find it difficult to decide whether to attempt one.

The best approach is to talk to your practitioner about your individual chance of success. Start the discussion early in pregnancy so you'll have time to carefully weigh the benefits and risks.

What are the benefits of having a VBAC?
A successful VBAC allows you to avoid major abdominal surgery and the risks associated with it — including a higher risk of excessive bleeding, which can lead to a blood transfusion or even a hysterectomy in rare cases, as well as a higher risk of developing certain infections. A c-section requires a longer hospital stay than a vaginal birth, and your recovery is generally slower and much more uncomfortable. And if you plan to have more children, you should know that every c-section you have increases your risk in future pregnancies of placenta previa and placenta accreta, in which the placenta implants too deeply and doesn't separate properly at delivery. These conditions can result in life-threatening bleeding and hysterectomy. Finally, if you were disappointed about having a previous c-section, you may feel a tremendous sense of pride and accomplishment at being able to deliver vaginally this time around.

What are the risks of attempting a VBAC?
Even if you're a good candidate for a VBAC, there's a small (less than 1 percent) risk that your uterus will rupture at the site of your c-section incision, resulting in severe blood loss for you and oxygen deprivation for your baby. This risk is somewhat higher if your labor needs to be induced or augmented. So some experts think it's reasonable to abandon the attempt at a VBAC if it looks like you're going to need oxytocin (Pitocin) to get your contractions going or keep them moving.

Also, if you end up being unable to deliver vaginally, you could endure hours of labor only to have an unplanned c-section. And while a successful VBAC is less risky than a scheduled repeat c-section, an unsuccessful VBAC requiring a c-section after the onset of labor carries more risk than a scheduled c-section. With an unplanned c-section after laboring, you have a higher chance of surgical complications, such as excessive bleeding that can lead to a blood transfusion or even a hysterectomy in rare cases, and infections of the uterus and the wound. And the risk of complications is even higher if you end up needing an emergency cesarean.

Finally, the risk of the baby having a serious complication (which can lead to long-term neurological damage or even death), while very small overall, is higher in women who undergo labor before a c-section. What kind of interventions will I need if I attempt a VBAC?If you decide to try a VBAC, you'll need continuous electronic fetal monitoring because a change in your baby's heartbeat is usually the earliest sign that there might be a problem. You'll also need an IV and have to refrain from eating anything during labor in case you later require an emergency c-section.