Risk of recurrent severe maternal morbidity in an urban safety-net health system

BACKGROUND: Rates of severe maternal morbidity are steadily increasing in the United States and are highest among women who are Black, publicly insured, or deliver at a safety-net hospital. There is limited information on the risk of severe maternal morbidity recurrence in subsequent births, particularly among socially vulnerable women. OBJECTIVE: To estimate the risk of severe maternal morbidity recurrence among singleton births in a large, public hospital system. STUDY DESIGN: We conducted a population-based cohort study using electronic medical record data on deliveries occurring at an urban public hospital between 2011 and 2020. We included all women with 2 singleton deliveries at >20 weeks of gestation (live or stillborn) during the study period and assessed severe maternal morbidity recorded at delivery or within 42 days postpartum. We used generalized linear models to estimate adjusted risk ratios, adjusted risk differences, and 95% confidence intervals for severe maternal morbidity at the subsequent birth, controlling for age, parity, self-reported race/ethnicity, insurance type, chronic hypertension and diabetes mellitus, and obesity at the index delivery. RESULTS: Between 2011 and 2020, there were 26,994 singleton deliveries to 21,638 women. Among 4368 women with 2 singleton births at >= 20 weeks of gestation, 4.8% (n=211) had severe maternal morbidity at the index birth, and 5.7% (n=250) had severe maternal morbidity at the subsequent birth. Severe maternal morbidity at the index birth was associated with an over 3-fold increased risk of severe maternal morbidity in a subsequent pregnancy (adjusted risk ratio, 3.65; 95% confidence interval, 2.65-5.03) and an excess risk of 12.9 per 100 deliveries (adjusted risk difference, 12.9; 95% confidence interval, 7.7-18.1). CONCLUSION: The results of our study suggest that women who experienced severe maternal morbidity in a previous birth are at increased risk for severe maternal morbidity recurrence and may warrant additional monitoring in subsequent pregnancies.