National Trends in Severe Maternal Morbidity by Insurance and Race and Ethnicity

Importance Rates of severe maternal morbidity (SMM) and mortality are rising in the US, disproportionally affecting racial and ethnic minority groups and Medicaid beneficiaries. Contemporary analyses investigating the intersectional impact of insurance and race and ethnicity on SMM are lacking. Objective To examine national trends in SMM and maternal mortality across deliveries and evaluate the intersectional association of insurance type and race and ethnicity with these outcomes. Design, Setting, and Participants This serial cross-sectional study used population-based National Inpatient Sample (a 20% stratified sample of hospital discharges) data on delivery hospitalizations from October 1, 2015, to December 31, 2022, in the US, with analyses completed between July 7, 2025, and January 30, 2026. Exposure Assessment of insurance (private vs Medicaid) and race and ethnicity independently and cross-classified into 10 intersectional groups. Main Outcomes and Measures Primary outcomes were composite SMM, nontransfusion-only SMM, and mortality. Multivariable logistic regression was used to estimate adjusted odds ratios (AORs) for outcomes across insurance, race and ethnicity, and intersectional groups. Results Among 27 341 986 weighted deliveries (mean [SD] maternal age, 29.0 [5.8] years; 6.3% of Asian or Pacific Islander, 16.2% of Black, 22.4% of Hispanic, 0.8% of Native American, and 54.3% of White race and ethnicity), 563 250 (2.1%) were complicated by SMM, 2320 of which (0.4%) resulted in death. From 2015 to 2022, composite SMM rates increased 40.5% (from 175.0 to 245.9 per 10 000 deliveries; P < .001), with 16 of 21 individual complications (76.2%) significantly increasing. Medicaid covered 11 658 119 weighted deliveries (45.5%), and included a greater proportion of Black, Hispanic, and Native American individuals than the privately insured population. Adjusted odds of composite SMM were elevated among all intersectional groups compared with White patients with private insurance (all P < .001). Within each racial and ethnic group, SMM odds were significantly higher with Medicaid vs private insurance (Asian or Pacific Islander: AOR, 1.28 [95% CI, 1.20-1.36]; Black: AOR, 1.13 [95% CI, 1.10-1.17]; Hispanic: AOR, 1.29 [95% CI, 1.24-1.34]; Native American: AOR, 1.44 [95% CI, 1.24-1.67]; White: AOR, 1.23 [95% CI, 1.20-1.26]). Significantly increased odds of mortality were primarily observed for Medicaid-insured Asian or Pacific Islander (AOR, 2.63 [95% CI, 1.25-5.52]), Hispanic (AOR, 1.97 [95% CI, 1.16-3.35]), and White (AOR, 2.15 [95% CI, 1.55-2.99]) patients but not for Medicaid-insured Black patients (AOR, 1.55 [95% CI, 0.99-2.41]). Conclusions and Relevance This serial cross-sectional study of births in the US found that racial and ethnic minority status was independently associated with elevated odds of SMM. Medicaid enrollment further compounded this risk and was associated with maternal mortality, suggesting underlying structural inequities that accompany Medicaid coverage rather than a direct effect of insurance type. Addressing these structural barriers through policy reform, including equitable reimbursement and expanded preconception coverage, is critical to mitigate these maternal health inequities.