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CME Credit Offered
CME Credit Offered
Abstract Award
Abstract Award
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Poster Session 3

(734) Preterm medically indicated labor induction and mode of delivery in patients with obesity

Friday, January 31, 2025
10:30 AM – 12:30 PM  
Objective: Maternal obesity is associated with cesarean delivery (CD) during induction of labor (IOL) at term; whether the same is true for patients with obesity undergoing preterm IOL is unknown. We sought to evaluate CD rates for patients with and without obese BMI undergoing medically indicated preterm IOL.

Study Design: This is a secondary analysis of a multicenter, randomized trial of singleton pregnancies at risk for preterm delivery. Participants with body mass index (BMI) >18.5 who underwent IOL for any indication were included. Planned CD and spontaneous labor were excluded. We compared delivery mode among participants undergoing preterm IOL by body mass index (BMI) at delivery: non-obese 18.5-29.9, class 1 30-34.9, class 2 35-39.9, class 3 > 40. The primary outcome was incidence of CD by BMI class. Chi-square, ANOVA and multivariable regression tests determined the strength of association.

Results: Of 1236 included participants, 482 had non-obese BMI (39%); 288 (23%), 220 (18%) and 246 (20%) had class 1-3 obesity. Pregnancies with class 1-3 obesity were more likely to be of Black race (20% for non-obese; 27%, 29% and 37% for class 1-3) or have hypertension (HTN) (6% non-obese; 13%, 21%, 33% class 1-3) or gestational diabetes (GDM) (6% non-obese; 13%, 18%, 21% class 1-3) (p values < .0001). In a univariate analysis, those with obesity were more likely to undergo unplanned CD than their non-obese counterparts (p< .0001). In a multivariable analysis adjusted for nulliparity, advanced maternal age, HTN, GDM, and treatment group, participants with class 1-3 obesity were more likely to undergo CD than their non-obese counterparts (class 1 aOR 1.62, 95% CI 1.12-2.36, class 2 aOR 2.30, 95% CI 1.55-3.41, class 3 aOR 2.96, 95% CI 2.02-4.33).

Conclusion: These novel findings suggest that while participants with obesity are more likely to undergo CD during medically indicated pre-term IOL, the majority still deliver vaginally. This data may aid in counseling patients undergoing medically indicated pre-term delivery who have obese BMI.