Impact of Maternal Obesity on Delivery Outcomes Following Labor Induction: A Single-Center Retrospective Cohort Study

This study evaluated the association between body mass index (BMI) at the onset of labor induction and delivery outcomes, including instrumental delivery, emergency cesarean section, labor duration, and cumulative oxytocin dose among singleton term pregnancies.

We conducted a retrospective cohort study of singleton term pregnancies undergoing labor induction at a tertiary perinatal center. We analyzed BMI at induction onset as a continuous variable and applied multivariable regression models to evaluate instrumental delivery, emergency cesarean section, labor duration, and cumulative oxytocin dose. We also performed sensitivity analyses using pre-pregnancy BMI, models additionally adjusting for gestational weight gain and pregnancy complications, and restricted-indication analyses.

Delivery BMI was not significantly associated with instrumental delivery (adjusted OR 0.96 per 1 kg/m² increase; 95% CI 0.92-1.00), emergency cesarean section (adjusted OR 1.03; 95% CI 0.99-1.07), or labor duration. In contrast, cumulative oxytocin dose increased with higher delivery BMI (β = 0.04 per 1 kg/m² increase; 95% CI 0.01-0.07), corresponding to approximately 20% greater oxytocin requirement per 5 kg/m² increment in this cohort. This pattern persisted across sensitivity analyses.

Higher maternal BMI at induction onset was associated with greater oxytocin requirements, while no clear associations were observed with mode of delivery or labor duration.