Importance: Little is known about the association between sickle cell disease (SCD) and severe maternal morbidity (SMM).
Objective: To examine the association of SCD with racial disparities in SMM and with SMM among Black individuals.
Design, setting, and participants: This cohort study was a retrospective population-based investigation of individuals with and without SCD in 5 states (California [2008-2018], Michigan [2008-2020], Missouri [2008-2014], Pennsylvania [2008-2014], and South Carolina [2008-2020]) delivering a fetal death or live birth. Data were analyzed between July and December 2022.
Exposure: Sickle cell disease identified during the delivery admission by using International Classification of Diseases, Ninth Revision and Tenth Revision codes.
Main outcomes and measures: The primary outcomes were SMM including and excluding blood transfusions during the delivery hospitalization. Modified Poisson regression was used to estimate risk ratios (RRs) adjusted for birth year, state, insurance type, education, maternal age, Adequacy of Prenatal Care Utilization Index, and obstetric comorbidity index.
Results: From a sample of 8 693 616 patients (mean [SD] age, 28.5 [6.1] years), 956 951 were Black individuals (11.0%), of whom 3586 (0.37%) had SCD. Black individuals with SCD vs Black individuals without SCD were more likely to have Medicaid insurance (70.2% vs 64.6%), to have a cesarean delivery (44.6% vs 34.0%), and to reside in South Carolina (25.2% vs 21.5%). Sickle cell disease accounted for 8.9% and for 14.3% of the Black-White disparity in SMM and nontransfusion SMM, respectively. Among Black individuals, SCD complicated 0.37% of the pregnancies but contributed to 4.3% of the SMM cases and to 6.9% of the nontransfusion SMM cases. Among Black individuals with SCD compared with those without, the crude RRs of SMM and nontransfusion SMM during the delivery hospitalization were 11.9 (95% CI, 11.3-12.5) and 19.8 (95% CI, 18.5-21.2), respectively, while the adjusted RRs were 3.8 (95% CI, 3.3-4.5) and 6.5 (95% CI, 5.3-8.0), respectively. The SMM indicators that incurred the highest adjusted RRs included air and thrombotic embolism (4.8; 95% CI, 2.9-7.8), puerperal cerebrovascular disorders (4.7; 95% CI, 3.0-7.4), and blood transfusion (3.7; 95% CI, 3.2-4.3).
Conclusions and relevance: In this retrospective cohort study, SCD was found to be an important contributor to racial disparities in SMM and was associated with an elevated risk of SMM among Black individuals. Efforts from the research community, policy makers, and funding agencies are needed to advance care among individuals with SCD.