The Contribution of Neighborhood Context to the Association of Race with Severe Maternal Morbidity

Objective Severe maternal morbidity (SMM) has disproportionate frequencies among racial minorities and those of socioeconomic disadvantage, with people of Black race consistently having the highest proportion. Neighborhood level deprivation has been associated with maternal morbidity and mortality, including adverse pregnancy outcomes. We sought to explore the relationship between neighborhood socioeconomic disadvantage and SMM and describe how neighborhood context impacts the relationship between race and SMM. Study Design We performed a retrospective cohort analysis of all delivery admissions in a single health care network from 2015 to 2019. Area deprivation index (ADI) was used to represent neighborhood socioeconomic disadvantage and is a composite index of neighborhood that spans income, education, household characteristics, and housing. The index ranges from 1 to 100 with higher values indicating higher disadvantage. Logistic regression assessed the relationship between ADI and SMM and estimated the effect that ADI has on the relationship between race and SMM. Results Of the 63,208 birthing persons in our cohort, the unadjusted incidence of SMM was 2.2%. ADI was significantly associated with SMM, with higher values conferring higher risk for SMM (p< 0.001). The absolute risk of SMM increased roughly by 1.0% from the lowest to highest ADI value. Those of Black race had the highest unadjusted incidence of SMM compared with the referent group (3.4 vs. 2.0%) and highest median ADI (92; interquartile range [IQR]: 20). In the multivariable model, in which the primary exposure was race and ADI was adjusted for, Black race had a 1.7 times odds SMM when compared with White race (95% confidence interval [CI]: 1.5-1.9). This association was attenuated to 1.5 adjusted odds when controlling for ADI ( 95% CI: 1.3-1.7). Risk attenuation for SMM was not seen in other race categories. Conclusion Neighborhood context contributes to SMM but does not explain the majority of racial disparities.