Risk associated with planned mode of delivery in women with obesity: a large population-based retrospective cohort study.

Background/objective: As the pregnancy progresses, a decision about planned mode of delivery must be made. There is no consensus on optimal mode of delivery among pregnant women with obesity. We aimed to assess the risks associated with planned mode of delivery in women with obesity.

Methods: This large population-based retrospective cohort study included 27472 nulliparous women with obesity who had live, singleton, and uncomplicated term gestations between April 1st 2012 and March 31st 2019. Planned mode of delivery included waiting for spontaneous labor, a plan for induction of labor, and planned non-labor cesarean section (NLCS). NLCS was defined as an elective CS that would happen before the pregnant woman goes into labor. The most common reasons for NLCS include maternal request, fetal position, and repeated CS. Adverse Outcome Index (AOI) was the primary outcome, a binary composite of 10 maternal-neonatal outcomes. Overall, maternal-specific, and neonatal-specific AOI scores were analyzed. Analyses were conducted using multivariable regression models and were stratified by each week of gestational age and by obesity class.

Results: Planned NLCS was associated with reduced risk of overall, maternal-specific, and neonatal-specific AOI by 41% (adjusted risk ratio [aRR]: 0.59, 95% confidence interval [CI]: 0.50-0.70), 54% (aRR: 0.46, 95% CI: 0.35-0.60), and 30% (aRR: 0.70, 95% CI: 0.57-0.87) respectively when compared to spontaneous labor at term gestation. There was no statistically significant difference in overall AOI when comparing planned induction of labor to spontaneous labor (aRR: 1.03, 95% CI: 0.96-1.10).

Conclusion: Among women with obesity, NLCS may be considered as an option for planned mode of delivery due to the decreased AOI risk. However, further research on the association between NLCS and severe outcomes is needed. Shared decision making between patient and practitioner regarding plan for delivery remains paramount in the provision of quality obstetrical care.