Influences of Maternal Obesity on Induction of Labor Requiring Cervical Ripening

Statement of the Problem Although obese women are less likely to initiate spontaneous labor than normal weight women, have longer labors, and higher rates of cesarean birth, evidence suggests little is known about the most effective methods for labor induction requiring cervical ripening in women with obesity. Using a population-based sample we evaluated the relationships between maternal obesity and methods for induction of labor requiring cervical ripening. Methods This retrospective cohort study used data from 41,359 women in the nationally representative Consortium of Safe Labor (CSL) dataset, collected from 2006 to 2012. Women with a low risk pregnancy (cephalic, singleton, and term gestation), undergoing induction of labor were included. The primary outcome of this study was cesarean birth after the use of cervical ripening methods. The secondary outcome was the time to birth with the use of cervical ripening methods. Binomial regression models and a survival analysis were adjusted for age, parity, race, insurance, and hospital type. Results Of the 41,359 cases included in the study, 6,035 women received one or more cervical ripening methods for induction of labor. The odds for cesarean birth in the vi highest obesity category (obese cat 3) were lower after using misoprostol [aOR 3.44; CI 1.95-6.07] than using other prostaglandins [aOR 7.03; CI 3.98-12.43], and lower using mechanical means [aOR 3.69; CI 2.04-6.68} then using either prostaglandin [aOR 3.94; CI 2.67-2.54] compared to normal weight women. The time to birth in the highest obesity category (Obese Cat 3) had higher hazard after using other prostaglandins [aHR 1.62; CI 1.20-2.11] and lower hazard after using mechanical means [aHR .91; CI .65-1.28] when compared to the use of misoprostol. Conclusions These data suggest women with obesity have more cesarean births with the use of other prostaglandins for cervical ripening than with the use of mechanical means when misoprostol is the comparison group. Women with obesity also require a longer time to birth after using other prostaglandins and a shorter time to birth after using mechanical means when compared to using misoprostol. Clinicians can better support women with obesity requiring cervical ripening for induction of labor with careful consideration of cervical ripening method choice and effective counseling on length of labor induction, and risk for cesarean birth