Hypertension and Diabetes as Drivers of Severe Maternal Morbidity Across Age Race Region and Income in the United States

Background Severe Maternal Morbidity (SMM), defined as unexpected outcomes of labor and delivery with significant health consequences, continues to rise in the United States and disproportionately affects marginalized communities. Chronic conditions such as hypertension and diabetes are known risk factors, but the interplay of these comorbidities with social determinants of health remains poorly characterized. Methods We analyzed 2019–2020 delivery hospitalizations from the National Inpatient Sample (NIS), a nationally representative dataset. SMM was defined using CDC and AIM criteria (excluding transfusion-related events). We conducted multivariate logistic regression to estimate adjusted odds ratios (aORs) for SMM, stratified by diabetes and hypertension status, while controlling demographic, clinical, and socioeconomic variables. Results Among 7 million delivery hospitalizations, 0.8% involved SMM. SMM prevalence was 1.4% among individuals with diabetes and 3.2% with hypertension. Younger individuals (ages 20–24) had higher odds of SMM in the hypertension subgroup (aOR 1.49; 95% CI: 1.23–1.82), contrary to general trends. Racial and income disparities persisted across subgroups. Black and Hispanic patients had lower adjusted SMM odds in diabetic and hypertensive subgroups, respectively. Increased healthcare utilization (longer stays, higher diagnosis/procedure counts) was consistently associated with SMM. Conclusions This study highlights how age, race, income, and regional factors interact with hypertension and diabetes to shape SMM risk. Findings underscore the urgency of integrating chronic disease management into maternal care and tailoring interventions to the unique needs of socioeconomically and demographically vulnerable populations. Community-based care models and enhanced preconception screening are essential to reducing disparities.