Elucidating the role of overweight and obesity in racial and ethnic disparities in cesarean delivery risk

Purpose: We aimed to quantify the extent to which overweight and obesity explain cesarean delivery risk among women of different racial and ethnic backgrounds. Methods: Using administrative records for 216,481 singleton, nulliparous births in New York City from 2008 to 2013, we calculated risk ratios, risk differences, and population attributable fractions for associations between body mass index (BMI) and cesarean, stratified by race and ethnicity. Results: The population attributable fraction (95% confidence interval) for BMI was 6.8% (6.2%–7.3%) among Asian, 10.9% (10.4%–11.4%) among White, 14.6% (13.7%–15.5%) among Hispanic, and 17.4% (16.2%–18.6%) among Black women. Although overweight and obesity were most prevalent among Black and Hispanic women, the risk gradient was strongest among Whites (adjusted risk ratio [95% CI] from 1.37 [1.33–1.41] for overweight to 2.23 [2.07–2.39] for class III obesity). Additional adjustment for gestational complications partially attenuated associations, and accounting for delivery hospital eliminated the stronger gradient among White women. Conclusions: Prepregnancy overweight and obesity contribute proportionally more to cesarean risk among Black and Hispanic women because of higher prevalence compared to White or Asian women. Although preconception weight management is important to decrease cesarean risk, results encourage attention to clinical approaches in low-risk pregnancies to mitigate racial and ethnic perinatal disparities.