Correlation between maximum cervical dilatation at cesarean delivery and subsequent vaginal birth after cesarean delivery

Objective: To determine whether the extent of cervical dilatation at cesarean delivery affects the subsequent vaginal birth after cesarean (VBAC) rate. Methods: Relevant records of the index pregnancy (group I) were reviewed for cervical dilatation at cesarean delivery, oxytocin use, indication, neonatal weight, and epidural use. The records of the subsequent pregnancy (group II) were reviewed for successful VBAC rates, neonatal weight, oxytocin, and epidural use. Results: There were 1917 patients in the study. The indications for cesarean in group I were malpresentation (5.1%), fetal distress (14.9%), and arrest disorders (80%). In group II, the VBAC success rates were 73% for previous malpresentation and 68% for previous fetal distress. In those with previous cesarean deliveries for arrest disorders with cervical dilatation at 5 cm or less, the VBAC success rate was 67%. It was 73% for 6-9 cm dilatation and 13% for the fully dilated group (P < .05). Conclusions: Patients who attempt a VBAC may be counseled that a cesarean delivery at full dilatation is associated with a reduced chance of a subsequent successful VBAC.