Severe maternal morbidity (SMM) is 50 to 100 times more common than maternal death, and has increased disproportionately among ethnic/racial minority women in the United States. However, specific knowledge about how the types and timing of severe maternal morbidities deferentially affect ethnic/racial minority women is poorly understood. This study examines racial/ethnic disparities in severe maternal morbidity during antepartum (AP), intrapartum (IP), and postpartum (PP) hospital admissions in the United States (US) for 2002-2014. We identified AP, IP, and PP hospitalizations in the National Inpatient Sample. Distribution of sociodemographic, behavioral and hospital characteristics, insurance, comorbidities, and SMM occurrence was summarized using descriptive statistics. Through Joinpoint regression, temporal SMM trends of hospitalizations were examined and stratified by race. Multivariate logistic regression assessed the association between race and SMM. We found black women have the highest proportion of SMM across all pregnancy intervals with a 70% greater risk of SMM during AP after adjusting for all cofactors. In the PP period, Hispanic women's risk of SMM is 19% less when compared to white women. Racial/ethnic disparities in SMM vary in timing and SMM type. Systematic investigation is needed to understand risks to black women and the protective factors associated with Hispanic women in the PP. Addressing racial disparities in maternal morbidity and mortality requires national policies and initiatives tailored to black women that address the specific types and timings of life-threatening obstetric complications.
Keywords: Maternal mortality; Obstetric complications; Pregnancy; Reproductive health disparities; Severe maternal morbidity.