Patient- and Hospital- Level Disparities in Severe Maternal Morbidity: a Retrospective Multistate Analysis, 2015-2020.

The rate of severe maternal morbidity (SMM) in the United States (US) rose roughly 9% among all insured racial/ethnic groups between 2018 and 2020, disproportionately affecting racial and ethnic minority populations. Limited research on hospital-level factors and SMM found that even after adjusting for patient-level factors, women of all races delivering in high Black-serving delivery units had higher odds of SMM. Our retrospective cohort study augments the current understanding of multi-level racial/ethnic disparities in SMM by analyzing patient- and hospital- level factors using multistate data from 2015 to 2020. Because rises in SMM have been driven in part by an increase in blood transfusions, multivariable logistic regression models were employed to estimate the impact of patient- and hospital-level factors on the adjusted odds of experiencing any SMM, with and without blood transfusions, as well as blood transfusions alone. Our cohort consisted of 3,497,233 deliveries: 56,885 (1.63%) with any SMM, 16,070 (0.46%) with SMM excluding blood transfusion, and 45,468 (1.30%) with blood transfusions alone. We found that Black race, Hispanic ethnicity, and delivering at Black-serving delivery-units, both independently and interactively, increase the odds of any SMM with or without blood transfusions. Our findings illustrate the persistence of structural- and individual- level racial and ethnic disparities in maternal outcomes over time and emphasize the need for multi-level public policies to address racial/ethnic disparities in maternal healthcare.