For a woman with a previous cesarean, answering these questions is a critical step to deciding between a repeat Cesarean (RCS) and a vaginal birth after Cesarean (VBAC).
According to the NIH VBAC Consensus Statement, an estimated 74 percent of women that plan a VBAC will have a successful VBAC. The success rates vary between 54 percent and 94 percent depending on a several factors, including induction or augmentation of labor, pregnancy length, vaginal birth history, reason for previous Cesarean, cervical readiness, race and ethnicity, health of the mother, socioeconomic status, region, marital status and type of hospital.
The following factors are based upon current evidence and point to higher rates of successful VBAC*:
- A previous vaginal delivery (before or after a cesarean delivery)
- Nonrecurring reason for Cesarean delivery (such as malposition, breech, multiples, fetal distress, placenta previa)
- Previous delivery of a baby weighing less than 4,000 grams (8 pounds and 13 ounces)
Start of and During Labor:
- Spontaneous labor (no induction or augmentation)
- Pregnancy length of 40 weeks or less
- Greater cervical dilation at admission
- Greater cervical dilation at rupture of membranes
- Cervical effacement that reaches 75-90 percent upon admission
- A single, vertex position baby (head down)
- The baby’s head being engaged or lower in the pelvis
- A higher Bishop score (a scoring system to estimate the success of induction)
While the medical factors listed above define an “ideal” candidate, you do not need to fit into all the areas to be a good candidate, and most women do not fit into all the categories.