| Anemia is the most common nutritional deficiency in the world. Maternal anemia during pregnancy is associated with adverse birth outcomes, and increased perinatal morbidity and mortality. In the United States, the prevalence of third trimester anemia among low income pregnant women is about 29% and has not changed since the 1980s. Low adherence has been linked to the ineffectiveness of iron supplementation programs but limited data are available about adherence. The purpose of this study was to better understand factors associated with adherence to use of iron containing prenatal multivitamin/mineral supplements (PNS) among low income pregnant women.; Adherence to PNS was assessed by pill counts in 244 pregnant women receiving care at a public health prenatal clinic. Maternal characteristics associated with adherence were identified using predictive modeling. On average, women took 74% of PNS as prescribed. Multivariate regression analysis revealed that factors associated with adherence differed between black and white women. White women having more than a high school education, being unmarried, nulligravid and a smoker were more likely to adhere, while supplement use prior to current pregnancy was an important predictor of adherence in black women. Among both the ethnic groups, women with higher gestational age at their first prenatal visit were more likely to adhere.; Side-effects reported among users of PNS with 0 mg, 30 mg, and 60 mg dose of iron, and their influence on pill count adherence was examined. Most women reported experiencing one or more side-effects, but only 12% attributed them to the use of PNS. Most thought the symptoms occurred due to the pregnancy state itself. Only loss of appetite was significantly negatively associated with adherence, and only among women with high school education or less. Measurement error in self-report and pill count adherence measures was examined by comparing them to a more objective Medication Event Monitoring System (MEMS) in a sub-sample. Both self-reports and pill counts overestimated adherence, but pill count correlated better (0.62) with MEMS, than the self-report adherence (0.35). The linear approximation calibration resulted in a significantly lower estimate of adherence (64%), than the observed pill count adherence (74%). |
