Comparison of maternal mortality and morbidity between trial of labor and elective cesarean section among women with previous cesarean delivery

Objective: This study was undertaken to assess the safety of trial of labor after previous cesarean delivery. Study design: Retrospective cohort study of 308,755 Canadian women with previous cesarean delivery between 1988 and 2000. Occurrences of in-hospital maternal death, uterine rupture, and other severe maternal morbidity were compared between women with a trial of labor and those with an elective cesarean section. Results: Rates of uterine rupture (0.65%), transfusion (0.19%), and hysterectomy (0.10%) were Hysterectomy significantly higher in the trial-of-labor group. Maternal in-hospital death rate, however, was volume lower in the trial-of-labor group (1.6 per 100,000) than in the elective cesarean section group (5.6 per 100,000). The association between trial of labor and uterine rupture was stronger in low volume (<500) than in high volume (greater than or equal to500 births per year) obstetric units. Conclusion: Trial of labor is associated with increased risk of uterine rupture, but elective cesarean section may increase the risk of maternal death. (C) 2004 Elsevier Inc. All rights reserved.