Maternal Outcomes Associated With Induction Of Labor At 39 Weeks Compared With Expectant Management

INTRODUCTION: To compare the risk of maternal complications associated with induction of labor (IOL) at 39 weeks gestation with that of expectant management (EM) beyond 39 weeks gestation. METHODS: This is a retrospective cohort analysis of singleton non-anomalous pregnancies in the United States between January 2015 and December 2017. Data was abstracted from the CDC National Center for Health Statistics from the Division of Vital Statistics. Analyses compared IOL at 39 weeks of gestation versus EM with delivery between 40 and 42 weeks of gestation. Maternal outcomes of interest included need for blood transfusion, development of chorioamnionitis, intensive care unit (ICU) admission, uterine rupture, unplanned hysterectomy, and cesarean delivery (CD). Logistic-binomial regression analysis was performed to calculate the relative risk for the outcomes of interest, adjusting for confounding variables. RESULTS: There were 1,987,757 pregnancies included for analysis with 499,920 women in the IOL group. The risk of chorioamnionitis was 1.39% for IOL and 2.47% for EM (aRR: 0.58, 95% CI [0.56-0.59]). The risk of CD was 14.7% in the IOL group versus 14.8% in the EM group (aRR: 0.94, 95% CI [0.93-0.94]). Unplanned hysterectomy in the IOL group was 0.03% versus 0.02% in the EM group (aRR: 1.30, 95% CI [1.05-1.59]). There were no differences in risk of blood transfusion, ICU admission, and uterine rupture between the IOL and EM groups. CONCLUSION: Women who underwent IOL at 39 weeks had a lower risk of chorioamnionitis and CD compared to EM. However, there was a higher risk of unplanned hysterectomy with IOL at 39 weeks.