Vaginal birth after cesarean (VBAC) describes vaginal delivery by a woman who has undergone a cesarean delivery in a prior pregnancy. Trial of labor after cesarean (TOLAC) describes the process of attempting a vaginal delivery after having had a cesarean delivery. Patients often ask: How safe is it? Who should try it? Will I be successful? The overall success rate for having a vaginal birth after one cesarean delivery has remained constant at approximately 74%. This success rate is dependent on the reason for the first c-section (breech baby versus fetal heart rate decelerations during labor versus the 'head didn't come down and an infection set in during labor'). For example, if the reason for a csection is the mother pushed for 3 hours and the head didn't come down, the success rate is a little less than if the mother had a csection for a breech baby. VBAC's are also more successful and safer when labor occurs naturally versus inducing labor.
The risk of attempting a TOLAC is there is a small chance for uterine rupture. This occurs because the prior scar on the uterus is not as strong as the surrounding uterine wall and can break open. The rate of this occurring after one prior csection at term (in the vast majority of cases) is less than 1%, or 0.5-0.7%. Given this small, but serious risk to the mother and baby, VBAC should not be attempted unless anesthesia is readily available and there is an open, experienced operating room team available to assist in the case of an emergency cesarean section.
For patients who are undecided whether or not they want to try for a VBAC in a subsequent pregnancy, I encourage them to be patient and see what happens. As a pregnancy reaches term, if the cervix is softening, the head is low in the pelvis, etc., there is a very good chance that a TOLAC will be successful and safe. Additionally, if the mother is planning on having more than 2-3 pregnancies, it is much safer for her to have vaginal births as compared to several csections.
At the beginning of a pregnancy, it is very important to talk to your doctor about your prior OB history and about your expectations, fears, and hopes for Your current pregnancy. Your doctor should listen and also explain their preferences and experiences. This kind of open communication starting at the beginning of your doctor-patient relationship will help achieve a happy experience!