464: Antepartum anemia and racial/ethnic disparities in blood transfusion in california


      Non-Hispanic Black women experience the highest rate of severe maternal morbidity (SMM) in the United States, a risk persistent after controlling for socioeconomic status. Our objective is to assess whether racial/ethnic disparities of antepartum iron deficiency anemia (IDA) contribute to disparities in blood transfusion, the major component of SMM, at birth.

      Study Design

      Using data from the Office of Statewide Health Planning and Development in California, we performed a retrospective population-based cohort study using 2,802,622 vital records linked to birth hospitalization discharge data from 2007-2012. We estimated racial/ethnic differences in blood transfusion before and after adjusting for differences in IDA present on admission for birth. We then evaluated the association between IDA and blood transfusion in racial/ethnic groups separately. We estimated odds ratios and population attributable risks (PAR) using multivariable logistic regression models adjusted for the Obstetric Comorbidity Index, insurance, education, parity, and timing of prenatal care initiation.


      Black women had the greatest prevalence of IDA at hospital admission for birth (8.2%) and blood transfusion during hospitalization (4.3%). The elevated risk of blood transfusion in Black women was significantly reduced by adjusting for IDA (aOR 1.61 to aOR 1.33; Table 1). Adjustment for IDA had a minimal impact on disparities in blood transfusion for other racial/ethnic groups, particularly in Asian/Pacific Islander women (aOR 1.47 for confounders, aOR 1.45 for confounders and IDA). Among Black women, the PAR suggested that the absence of IDA in Black women correlates with a decrease in 28.4 blood transfusions per 10,000 births (Table 2).


      Treatment of antepartum IDA has the potential to reduce blood transfusions, the leading contributor to SMM, for all pregnant women. This reduction will be the highest among non-Hispanic Black pregnant women.
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