The Impact of Neighborhood-level Racial and Economic Segregation on Low-Risk Cesarean Delivery among Black, White, and Biracial (Black/White) Individuals

Background: Research has established Black-White low-risk cesarean delivery (CD) disparities; however, it is unknown how select structural factors are involved in this disparity and whether Biracial (Black/White) individuals face similar disparities. Our objective was to estimate the association of low-risk CD among Bblack, Wwhite and Bbiracial individuals, and determine whether these associations vary by neighborhood level racial and economic segregation. Methods: 385,825 nulliparous, term, singleton, vertex births among Black, White, and Biracial individuals in California (2011-2019) were included from a statewide administrative birth cohort of birth certificates linked to hospital records. We used a generalized estimating equation, Poisson regression stratified by Index of the Concentration of the Extremes (ICE) tertile to estimate risk ratios (RR) for low-risk CD across tertiles of racial and ethnic disparities. The Index of the Concentration at the Extremes (ICE; American Community Survey) is a measure of racial and economic segregation where ICE tertiles 1-3 rank census tracts from most to least impacted by inequality. Models were adjusted for maternal age at delivery. We also assessed the potential mediating roles of socioeconomic factors, maternal characteristics, and quality of care variables through regression-based mediation analyses. Results: The risk of CD was greatest in Black individuals (30.71%), followed by Biracial (25.47%) and White (24.98%). In age adjusted models, Black individuals had a higher CD risk than White individuals across all tertiles, with similar estimates within racial and economic segregation tertile (aRR _tertile1 : 1.34; 95% CI: 1.21, 1.36, aRR _tertile2 : 1.35; 95% CI: 1.30, 1.39, aRR _tertile3 : 1.40; 95% CI: 1.33, 1.47). Biracial individuals had a higher risk for CD than White individuals in all tertiles after age adjustment (aRR _tertile1 : 1.16; 95% CI: 1.10, 1.22, aRR _tertile2 : 1.18; 95% CI: 1.10, 1.27, aRR _tertile3 : 1.18; 95% CI: 1.08, 1.29). Select socioeconomic factors and maternal characteristics were identified as mediators. Conclusions: The low-risk CD disparity by race persisted across all ICE tertiles. Biracial individuals experienced a higher risk of CD than White, but not Black individuals suggesting that they may experience simultaneous health advantages and disadvantages relative to their monoracial counterparts.