Efficacy of multiple micronutrient supplements during pregnancy on zinc status among pregnant women in Ghana: a randomized controlled trial.

BACKGROUND: Multiple micronutrient deficiencies, including zinc deficiency, remain highly prevalent among pregnant women in many low- and middle-income countries and are associated with a multitude of adverse outcomes. OBJECTIVE: The objectives of this analysis were to assess the impacts of prenatal multiple micronutrient supplements (MMS) compared to iron and folic acid (IFA) supplements on maternal zinc status among pregnant women at 36 weeks gestation and assess associations with birth outcomes. METHODS: We analyzed plasma zinc concentrations at baseline (< 20 weeks gestation) and late pregnancy (36 weeks gestation) from a sub-set of pregnant women randomly assigned to receive either daily MMS (containing 30 mg/d zinc) or IFA supplements (n = 125/group) in the iLiNS DYAD trial in Ghana. Gestational and infant anthropometric outcomes were measured at birth. RESULTS: At baseline, mean + SD plasma zinc concentration was 61.9 + 13.6 μg/dL and 16.5% of women were zinc deficient. At 36 weeks gestation, mean + SD plasma zinc concentration was lower as compared to baseline, but did not differ significantly between groups (IFA: 52.2 + 8.1 μg/dL vs. MMS: 52.9 + 9.5 μg/dL; p = 0.25). Similarly, there was no difference in the estimated prevalence of zinc deficiency between groups at 36 weeks (IFA: 43.0% vs. MMS: 38.4%, p = 0.24). There were few significant associations between maternal plasma zinc concentrations or zinc deficiency and birth outcomes. CONCLUSIONS: Daily MMS supplementation for > 16 weeks during pregnancy did not significantly increase plasma zinc concentrations, and the prevalence of zinc deficiency increased over the course of pregnancy. Other complementary interventions to address both nutritional and underlying non-nutritional causes of zinc deficiency may be necessary to improve zinc status during pregnancy in this, and other vulnerable, populations. REGISTRY: The trial was registered as a clinical trial on ClinicalTrials.gov (NCT00970866) on September 2, 2009. https://clinicaltrials.gov/study/NCT00970866.