Mechanical labor induction in the obese population: a secondary analysis of a prospective randomized trial

Objective: The objective of this study was to estimate the influence of maternal body mass index (BMI) on progress and outcomes of labor induction using mechanical devices. Methods: This study was a secondary analysis of data collected during the Cook Catheter vs. Foley Catheter study, a series of prospective randomized trials of women requiring cervical ripening for labor induction. The duration, characteristics, and outcomes of labor were analyzed after stratification by BMI categories. Outcomes assessed included time from device insertion to delivery, successful ripening, cesarean delivery rates, and any maternal and neonatal adverse events. Results: One hundred and eighty-one patients were stratified according to BMI categories, with 102 study participants classified as normal weight (BMI ≤30) and 79 as obese (BMI >30). Maternal satisfaction from the induction process was significantly lower in the obese group compared to the normal weight group (5.95 ± 3.14 vs. 7.58 ± 2.7, respectively, in a 1–10 scale, p = 0.009). The cesarean delivery rate was similar in the normal weight and the obese groups (17.6 vs. 25.3 %, respectively, p = 0.27). No statistical differences were found in all other outcomes evaluated, including a sub-analysis of the different mechanical devices. Conclusions: During the process of mechanical cervical ripening, maternal satisfaction, but not objective obstetrical parameters, was influenced by increased maternal BMI. The trial is registered at ClinicalTrials.gov, no: NCT00604487. Trial registry name is “Induction of Labor in Patients with Unfavorable Cervical Conditions.”