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Medical/Surgical/Diseases/Complications

Poster Session 4

(931) Risk of Cesarean Delivery Stratified by BMI at Delivery

Wednesday, February 14, 2024
1:00 PM – 2:30 PM  
Location: Prince George's Exhibit Hall CDE, Lower Atrium Level
Objective: Studies have shown that obesity increases overall risk of cesarean delivery (CD) in a dose dependent fashion, but are often underpowered to assess higher stratifications of body mass index (BMI), particularly in super obese women (BMI > 50). The objective of this study is to evaluate overall risk of CD in super obese women and the impact on maternal and neonatal outcomes. 

Study Design: This was a population based retrospective study of all nulliparous women who delivered in the United States in 2021. Patients were stratified by BMI category at delivery excluding patients undergoing cesarean without labor. The primary outcome was the overall rate of CD, which was further stratified among inductions versus spontaneous labor. Secondary outcomes included maternal (transfusion, hysterectomy, ICU admission) and neonatal (NICU admission, mechanical ventilation, surfactant administration) composite adverse outcomes. Poisson regression with robust error variance was used to generate adjusted risk ratios (aRR) for each study outcome using normal BMI (18.5-24.9) as the referent adjusting for confounders.   

Results: There were 1,147,941 nulliparous women included in the analysis with 5,820 patients with BMI 50-59.9 and 594 patients with BMI ≥ 60. There was an increasing rate of CD with increasing BMI at delivery (range 7.3%-60.5%) with the highest risk among induced (aRR 1.35, CI 1.31-1.39) and spontaneously laboring (aRR 1.35, CI 1.28-1.42) women with BMI > 60; Figure 1. Similarly, the highest rate of both the maternal (range 0.57-1.16%) and neonatal (range 9.3-19.5%) composite adverse outcomes were in the highest BMI categories. Adverse outcomes remained significant after adjustment for gestational age at delivery.  

Conclusion: There is a substantial increased risk of CD as well as both adverse maternal and neonatal outcomes among nulliparous super obese women undergoing a labor trial. It is unknown whether these risks would be mitigated by elective cesarean delivery.