Pill count adherence to prenatal multivitamin/mineral supplement use among low-income women

In the United States, the prevalence of third trimester anemia among low-income pregnant women is 29% and has not improved since the 1980s. Although low adherence has been linked to the ineffectiveness of iron supplementation programs, data regarding adherence to supplementation in low-income women are currently lacking. Hence this study was conducted to better understand the factors associated with adherence to the use of iron-containing prenatal multivitamin/mineral supplements among low-income pregnant women. Adherence to supplement use was assessed by pill counts among 244 pregnant women of 867 women who were initially randomized to receive 1 of 3 prenatal supplements. All women received care at a public prenatal clinic. Maternal characteristics associated with adherence were identified using predictive modeling. Women took 74% of supplements as prescribed. Adherence was higher among non-Hispanic white women than among non-Hispanic black women (79% vs. 72%, P <= 0.01). Interactions of ethnicity with age group, smoking status, and prior supplement use were significant. Multivariate regression analysis stratified by ethnicity revealed that among the white women education beyond high school, unmarried status, nulligravidity, and smoking were positively associated with adherence. In contrast, among the black women, supplement use 3 mo prior to current pregnancy and no loss of appetite were positively associated with adherence. Further research investigating the influence of cultural factors is necessary to better understand adherence to supplement use and the differences in adherence among ethnic groups.