(482) Associations between antepartum anemia and uterine fibroids in pregnancy by race and ethnicity

Uterine fibroids cause anemia and create a significant burden of disease among Black women. Yet the degree to which fibroids contribute to racial disparities in antepartum anemia, a cause of severe maternal morbidity, is unclear. Our objectives were 1) to estimate the associations of uterine fibroids with antepartum anemia and 2) to evaluate associations across seven racial/ethnic groups.  

Study Design:

We conducted a retrospective cohort study of pregnant people in California from 2007 to 2018 who delivered at 20-42 weeks. Data were abstracted from a statewide database of vital records linked to delivery hospitalization discharge data. The primary exposure, uterine fibroids, and outcome, antepartum anemia, were identified using ICD codes. We used multivariable logistic regression modeling, stratified by self-reported race and ethnicity, to estimate odds ratios of antepartum anemia and to adjust for maternal characteristics (age, insurance, BMI, parity, timing of prenatal care) and clinical factors (vaginal bleeding and placental abruption).

Results:

Among 5,196,914 deliveries, the frequency of fibroids was 1.6%. Patients with fibroids were more likely to be older than 30 years (85.1% vs 46.3%), pregnant by assisted reproductive technology (0.8% vs. 0.1%), and have a cesarean birth (69.9% vs 31.9%). Black pregnant patients, with and without fibroids, had the highest frequency of anemia; of Black pregnant patients, with fibroids, 26% had anemia, and 16.1% of those without fibroids had anemia, respectively (Table 1). In the total study population, fibroids were associated with increased odds of antepartum anemia (aOR 1.78, 95% confidence interval 1.74-1.82). Fibroids increased the odds of antepartum anemia by at least 70% in every racial/ethnic group except American Indian/Alaska native.
 

Conclusion:

Independent of confounders, fibroids were significantly associated with 78% increased odds of antepartum anemia across nearly all racial/ethnic groups. Screening for anemia in patients with uterine fibroids may identify individuals at risk for severe maternal morbidity.