Risk factors associated with uterine rupture during trial of labor after cesarean delivery: a case-control study.

Objective: The purpose of our study was to thoroughly investigate the risk factors of uterine rupture in patients undergoing trial of labor after cesarean section.

Study Design: We conducted a case-control study of 70 patients with prior cesarean delivery with uterine rupture during trial of labor between January 1983 and June 1990. The risk factors of uterine rupture were identified, and the estimates of the relative risks were reported.

Results: The risk of uterine rupture was increased in patients who had an excessive amount of oxytocin, who had experienced dysfunctional labor, and who had a history of two or more cesarean deliveries. Epidural anesthesia, macrosomia, history of successful vaginal delivery after cesarean section, unknown uterine scar, and history of cesarean delivery because of cephalopelvic disproportion were not associated with uterine rupture.

Conclusions: We recommend that all patients with a history of cesarean delivery be observed closely for progression of labor. Recognition of an active-phase arrest disorder, despite adequate augmentation with oxytocin, requires operative delivery.