Effects of Antenatal Micronutrient Supplementation on Cortisol and Erythropoietin in Pregnant Nepalese Women

Abstract

Antenatal iron and multiple micronutrient supplementation improves birth weight. We examined whether this effect was mediated by reducing maternal stress and related factors that could compromise pregnancy outcomes. We examined late pregnancy serum erythropoietin (EPO) and cortisol in relation to maternal iron supplementation and iron status indicators (hemoglobin, Hb; ferritin, ferr; transferrin receptor, TfR) in 737 rural Nepalese women who participated in a 5-arm randomized, controlled micronutrient supplementation trial during pregnancy through 3 months postpartum. Women were randomized to receive vitamin A alone (as control), or with folic acid, folic acid+iron, folic acid+iron+zinc and a multiple micronutrient supplement (MN). EPO was ~0.5 mIu/ml lower (P<0.0001) in all groups receiving iron compared to the control group, with no difference in the folic acid only group. Cortisol was 1.3μg/dl lower (P=0.0422) in the MN group compared to the control group with no difference in other groups. Cortisol was associated with EPO (r = 0.20, P=0.008), TfR (r = 0.20, P=0.007), Ferr (−0.02, NS), and Hb (−0.15, p=0.053) in the control group. Hypoxia may elevate cortisol during iron deficiency. Reduction in mediators of maternal stress, including impaired erythropoeisis, is a likely mechanism by which iron and micronutrient supplementation may enhance birth weight. Support: USAID, Gates Foundation.