Maternal Overweight and Obesity during Pregnancy Are Associated with Neonatal, but Not Maternal, Hepcidin Concentrations.

BACKGROUND: Overweight or obesity among pregnant women may compromise maternal and neonatal iron status by upregulating hepcidin. OBJECTIVES: This study determined the association of 1) maternal and neonatal iron status with maternal and neonatal hepcidin concentrations, and 2) maternal prepregnancy weight status with maternal and neonatal hepcidin concentrations. METHODS: We examined hematologic data from 405 pregnant women and their infants from the placebo treatment group of a pregnancy iron supplementation trial in rural China. We measured hepcidin, serum ferritin (SF), soluble transferrin receptor (sTfR), and high-sensitivity C-reactive protein in maternal blood samples at mid-pregnancy and in cord blood at delivery. We used regression analysis to examine the association of maternal prepregnancy overweight or obese status with maternal hepcidin concentration in mid-pregnancy and cord hepcidin concentrations. We also used path analysis to examine mediation of the association of maternal prepregnancy overweight or obese status with maternal iron status by maternal hepcidin, as well as with neonatal hepcidin by neonatal iron status. RESULTS: Maternal iron status was positively correlated with maternal hepcidin at mid-pregnancy (SF: r = 0.63, P < 0.001; sTfR: r = -0.37, P < 0.001). Neonatal iron status was also positively correlated with cord hepcidin (SF: r = 0.61, P < 0.001; sTfR: r = -0.39, P < 0.001). In multiple linear regression models, maternal prepregnancy overweight or obese status was not associated with maternal hepcidin at mid-pregnancy but was associated with lower cord hepcidin (coefficient = -0.21, P = 0.004). Using path analysis, we observed a significant indirect effect of maternal prepregnancy overweight or obese status on cord hepcidin, mediated by neonatal iron status. CONCLUSIONS: In both pregnant women and neonates, hepcidin was responsive to iron status. Maternal prepregnancy overweight status, with or without including obese women, was associated with lower cord blood hepcidin, likely driven by lower iron status among the neonates of these mothers.