Induction of labor at 39 weeks and risk of cesarean delivery among obese women: a retrospective propensity score matched study.

OBJECTIVES: To evaluate if induction of labor (IOL) in obese women at 39 weeks of gestation decreases the risk of cesarean delivery (CD). METHODS: We conducted a retrospective propensity score matched study using the Center for Disease Control's (CDC's) Period Linked Birth-Infant Death data. The study population consisted of cephalic singleton births to women with BMI greater or equal to 30.0 kg/m2 who delivered at or beyond 39 weeks between 2013 and 2017. Women with prior CD were excluded. Women who underwent IOL at 39 weeks were propensity score matched 1:5 on the basis of CD risk factors to women who did not undergo IOL at 39 weeks but may have had an IOL at a later gestational age. Conditional logistic regression compared CD rates and maternal outcomes between obese women induced at 39 weeks with those not induced at 39 weeks. RESULTS: Our cohort consisted of 197,343 obese women induced at 39 weeks and 986,715 obese women not induced at 39 weeks. Overall, the risk of CD among women who had an IOL at 39 weeks was lower than those without an IOL at 39 weeks, 0.59 (0.58-0.60). The decrease in CD risk was more pronounced in multiparas, 0.47 (0.46-0.49) than nulliparas, 0.81 (0.79-0.83). When stratified by BMI, the effect of IOL on lowering CD risk was similar across all obesity classes. Aside from an increased risk of instrumental deliveries, morbidities were comparable in both groups. CONCLUSIONS: IOL at 39 weeks among obese women appears to lower the risk of CD, without compromising maternal outcomes.