Associations of anaemia and race with peripartum transfusion in three United States datasets

Abstract

Background - Transfusion complicates a significant proportion of births in the United States, and Black women have greater prevalence of transfusion at delivery than White women. Antepartum anaemia, a risk factor for peripartum transfusion, is more common among Black women than White women. We aimed to describe the racial distribution of antepartum anaemia in three national datasets and to evaluate the peripartum transfusion rate and characteristics of transfusion recipients, to investigate disparities in haemostatic outcomes.
Material and methods - We performed a retrospective analysis of Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Maternal-Fetal Medicine Units Network Cesarean Registry (CR), NICHD Consortium on Safe Labor Registry (CSL), and a cohort of deliveries at Universal Health Services hospitals (UHS). Univariable associations and multivariable logistic regressions were calculated between race, anaemia and transfusion. Covariates included age, parity, smoking, body mass index, type of insurance, and delivery mode.
Results - We included n=56,964 deliveries from CR (28% Black), 87,465 from UHS (12% Black), and 140,324 from CSL (24% Black). Anaemia prevalence was 8% in CR, 7% in UHS, and 13% in CSL. Anaemia was more common among Black patients (ORs 2.52, 2.61, and 1.48 respectively) and was associated with transfusion in all databases (ORs 6.46 [95% CI 5.78-7.22]; 5.79 [4.74-7.27]; 1.27 [1.18-1.37] respectively). After adjusting for covariates, Black patients had greater odds of transfusion than non-Black patients in CR (aOR 1.32 [1.16-1.50]), but not in UHS or CSL (aORs 1.19 [0.89-1.59] and 0.40 [0.36-0.44] respectively).
Discussion - In our retrospective cohort study using three US registries, we emphasized the link between anaemia and transfusion. Although anaemia was more prevalent among Black patients, the race-transfusion relationship differed between databases, indicating other unexplored factors are involved.