Antenatal Anemia and Perinatal Outcomes for Patients with Cardiac Disease in Pregnancy

This study aimed to assess whether pregnant patients with antenatal anemia in the setting of cardiac disease experience an increased risk of severe maternal morbidity (SMM) and other adverse pregnancy outcomes. This retrospective cohort study used the 2016–2021 National Readmissions Database to identify patients with cardiac disease delivering a singleton infant between 24 and 41 weeks gestation. Cardiac disease was identified by diagnosis codes and categorized based on modified World Health Organization (mWHO) criteria. Modified Poisson regression was used to assess the association between anemia and severe maternal morbidity, stratified by mWHO criteria. In a secondary analysis, iron deficiency anemia alone was considered the exposure of interest. Models were adjusted for age, median household income by ZIP code, primary payer, hospital size, hospital teaching status, delivery mode, and other comorbid conditions. Cardiac disease was identified in 61,542 patients in our cohort (47,767 [77.6%] with mWHO I–II disease and 13,775 [22.4%] with mWHO II/III+ disease). Of these patients, 10,257 (16.7%) had anemia. Weighted to provide national estimates, this sample results in a national estimate of 115,347 deliveries complicated by cardiac disease during the study period in the United States, of which 19,439 (16.7%) also had anemia. Anemia was associated with higher odds of SMM/mortality in people with mWHO I–II (aRR = 1.90, 95% CI: 1.73, 2.09) and mWHO II/III+ (aRR = 1.24, 95% CI: 1.18, 1.31) cardiac disease. Antenatal anemia was also associated with blood product transfusion, non-transfusion SMM/mortality, cardiac SMM, preterm birth, and cesarean delivery. This relationship persisted for the subgroup of patients with iron deficiency anemia. Antenatal anemia, including iron deficiency anemia, adversely impacts pregnancy outcomes in pregnant patients with cardiac disease. Identifying and treating this modifiable risk factor potentially offer an opportunity to reduce morbidity in this high-risk population.