ABSTRACT: OBJECTIVE:To clarify how race is associated with adverse maternal outcomes and risk for women aged 40 years or older. METHODS:This retrospective cohort study used the Nationwide Inpatient Sample for the years 1998-2014. Women aged 40-54 years were included. Race and ethnicity were categorized as non-Hispanic white, non-Hispanic black, Hispanic, Asian or Pacific Islander, Native American, other, and unknown. Temporal trends in severe maternal morbidity and overall comorbid risk by race in women aged 40 years or older were evaluated as were common pregnancy complications including preeclampsia, gestational diabetes, and cesarean delivery. Adjusted models were created to assess factors associated with severe morbidity. RESULTS:A total of 1,724,694 deliveries were included in this analysis. Severe maternal morbidity increased over the study period from 1.6% in 1998-2000 to 3.0% from 2013 to 2014. Black women had the highest rates of severe morbidity at both the beginning (2.4% in 1998-2000) and the end (4.9% in 2013-2014) of the study period. During this same period, comorbid risk based on medical conditions and other factors increased overall and individually by race. Black women also experienced the absolute largest increase from 1998-2003 to 2010-2014 in risk for acute renal failure, disseminated intravascular coagulation, transfusion, and hysterectomy. Pregnancy complications including preeclampsia, cesarean delivery, and gestational diabetes were more common at the end compared with the beginning of the study for black, white, and Hispanic women. The adjusted risk ratio for overall severe morbidity for black compared with white race was 1.81 (95% CI 1.76-1.87). Black women had a substantially higher risk of death than white women (risk ratio 4.71, 95% CI 3.36-6.61), and Hispanic women had more than twice the risk of death (risk ratio 2.13, 95% CI 1.48-3.07) as white women. CONCLUSION:Although black women older than 40 years were at increased risk for adverse outcomes and severe morbidity, this differential was of smaller magnitude than reported mortality risk.
