Objective: Previous studies suggest that labor induction is associated with an increased risk of cesarean delivery (CD), but more modern studies question this finding. In particular, it is uncertain how induction affects CD risk among women with gestational diabetes mellitus (GDM), who are often induced. Therefore, we sought to assess the risk of CD among women with GDM who presented for induction compared to those who presented in spontaneous labor.
Methods: Secondary analysis of a prospective cohort study of singleton pregnancies complicated by GDM. Women planning an elective or repeat cesarean were excluded. All women were delivered at a single institution. The primary outcome for this analysis was mode of delivery (CD vs. vaginal delivery). Women who presented for an induction were compared to those who presented in spontaneous labor (including rupture of membranes at 34 weeks or greater). Covariates, including gestational age at delivery were investigated as confounders and adjusted for if the p<0.05. The study had 80% power to detect an 18% decrease in the absolute rate of vaginal deliveries in the induction group compared to the spontaneous labor group with an alpha of 0.05.
Results: Of the 222 women meeting study inclusion criteria, 80 (36%) presented in spontaneous labor and 142 (64%) underwent labor induction. The overall CD rate was 21.6% (n=48). When comparing labor induction to spontaneous labor to, there was no significant difference in the CD rate (21.8% vs. 21.3% p=0.41). Women who were induced compared to those who labored spontaneously differed only with regard to BMI at delivery (p=0.04), and hypertension (p<0.01). Even after adjusting for these covariates, the risk of CD did not differ between groups (aOR 1.01 95% CI 0.51, 2.02). Moreover, the risk remained non-signification even when gestational age was included in the model.
Conclusion: Induction of labor among women with GDM is not associated with an increased risk of CD and should not be avoided in an attempt to minimize CD risk.
M.S. Hamel: None. M.B. Kole: None. D. Rouse: None. E. Werner: None.