The influence of intrapartum factors on risk of uterine rupture and successful vaginal birth after cesarean delivery.

Cesarean delivery is common and increasing over time. A prior cesarean birth increases the risk of both elective and emergency cesarean births and uterine rupture in a subsequent pregnancy. A range of factors, including labor characteristics, may influence the risk of these outcomes in the next pregnancy. Intrapartum factors associated with successful vaginal birth and lower risk of uterine rupture include the spontaneous onset of labor and advanced cervical dilatation. In contrast, need for induction and augmentation of labor are both factors associated with an increased likelihood of unsuccessful vaginal birth and risk of uterine rupture.