Women's Health Specialists of St. Louis
Obstetrics and Gynecology

Articles - Vaginal Birth After Cesarean

There are many reasons why cesarean deliveries are performed. Women who have had a cesarean delivery often ask if a vaginal delivery is a possible option for future pregnancies. Vaginal birth after cesarean (VBAC) has the advantage of decreased maternal discomfort and recovery time. Unfortunately, VBAC is not without risk. During a cesarean, the uterus is surgically opened. The scar that forms once the uterus heals is not as strong as normal uterine tissue. During a subsequent delivery, the scar can tear open. This is referred to as uterine rupture. When uterine rupture occurs it is a medical emergency as both the mother and baby are at risk.

In general, women who undergo VBAC have a low rate of uterine rupture. This rate is about 1% if the uterine scar is transverse or horizontal. It is very important for women to know that the scar on the skin may not necessarily be the same orientation as the scar on the uterus. For example, a woman may have a horizontal scar on the skin but the incision on the uterus may be vertical. Vertical scars on the uterus are associated with a greater risk of uterine rupture during labor. Women who have had more than one cesarean or who have had other uterine surgery may be at greater risk of uterine rupture as well. Because of this increased risk, only women with a single horizontal scar on the uterus should consider VBAC.

Women who are considering VBAC are candidates to attempt a vaginal delivery if they have a horizontal scar on the uterus, have no other uterine scars, and do not have any medical conditions that would prevent a safe vaginal delivery. In general, 60-80% of women who attempt vaginal birth after cesarean have a successful vaginal birth. Chances of success are greatest for women who have had a prior successful vaginal delivery sometime in the past, have normal spontaneous labor, had a cesarean for breech presentation, or had a cesarean early in labor without complete dilatation of the cervix. Women who have undergone a cesarean for the birth of a large infant are least likely to be able to successfully have a subsequent vaginal delivery. This is because in future pregnancies, they are likely to have another large infant that may not fit through the pelvis safely.

Women who are considering a VBAC need to review their delivery history with their obstetrician. Women who decide to attempt VBAC will have their labor managed as it would be normally with a few exceptions. For example, medications used to induce or stimulate labor are generally not recommended as they may increase the risk of uterine rupture. In addition to routine management, special attention is given to signs of distress from the baby or signs of uterine rupture. Women should choose a hospital where a cesarean can be performed emergently should a problem occur.