Maternal outcome monitoring: induction of labor versus spontaneous onset of labor-a retrospective data analysis

To determine the efficacy and maternal complication rates of induction of labor, and to identify a concrete point in time for induction with the lowest possible risk for adverse events. We designed a retrospective data analysis of all births at the general hospital of Vienna from 2003 to 2008 (n = 16,872) and compared maternal complications of induced labors from 38 or more weeks of gestation versus spontaneous deliveries. The ethical committee of the General Hospital of Vienna and the Medical University of Vienna monitored this study and provided approval. Women who had induction between 38 and 42 weeks of gestation (n = 1,254) had a significant higher risk for the need of a secondary cesarean (15.2 vs. 8.6%; p < 0.001) and a higher chance for abnormally adherent placentas (1.5 vs. 2.5%; p = 0.13). The amount of maternal blood loss was equal in both groups. Concerning the question when to induct labor, there was no significant difference of distribution of complications between induced labors at term and induction within the next 10 days. This study suggests that induction is associated with a higher risk for secondary cesareans and abnormally adherent placentas. The exact time of induction seems to be irrelevant between expected date of delivery and the next 10 days.