Disparities in hypertensive disorders of pregnancy and severe maternal morbidity: Evidence from a statewide birth cohort

Objective Hypertensive disorders of pregnancy (HDP) complicate 15% of pregnancies nationally and are a major contributor to severe maternal morbidity (SMM). We aimed to characterize temporal trends and demographic disparities in HDP incidence and evaluate the association between HDP and SMM in a statewide cohort. Methods This study is a descriptive and regression‐based analysis of a retrospective cohort of Wisconsin births from 2017 to 2023. Data were obtained from the Wisconsin Hospital Association (WHA). Subtypes of HDP were identified using ICD‐10 codes. Incidence rates of HDP per 10,000 births and average annual percent changes (AAPC) were estimated using Poisson regression and examined across demographic variables. Outcomes measured included SMM incidence, AAPCs, and SMM indicators by HDP. Results Among 388,250 pregnancies, the incidence of nearly all HDP subtypes rose from 2017 to 2023. Severe pre‐eclampsia had the highest AAPC (11.8%; 95% confidence interval [CI], 10.6%–13.0%). HDP incidence was highest in urban areas, though the AAPC in preeclampsia was greater in rural areas (8.7%; 95% CI, 7.1%–10.3%; p = 0.004). Black patients experienced higher incidences of HDP, with significant differences in AAPC for HDP overall, chronic hypertension, and severe preeclampsia ( p < 0.001). Patients with HDP had higher SMM rates compared to those without, though the AAPC in SMM did not differ by HDP status. Conclusion These findings highlight a growing burden of HDP in Wisconsin, with an increase in severe preeclampsia incidence and disparities by geography and race. Targeted interventions in rural areas and for Black patients are needed to improve disparities in HDP incidence and reduce SMM across Wisconsin.