High Burden of Vitamin D Deficiency in Pregnancy and its Association with Low Birth Weight in a Prospective Cohort in South India

Abstract

ObjectiveThis study was conducted to determine the prevalence of vitamin D deficiency in a prospective cohort of pregnant women and its association with birth outcomes in Bangalore, India.MethodsPregnant women (n=419) were recruited in their first trimester to a perinatal cohort study between 2008 and 2014 and followed up until delivery. Vitamin D status was assessed through determination of serum 25‐hydroxyvitamin D (25(OH)D) using tandem liquid chromatography mass spectrophotometry (LCMS/MS, CV 1.6%) in maternal samples at enrollment and in cord blood at delivery. Binomial and linear regression models were used to evaluate the associations between maternal and infant vitamin D status and with birth outcomes, including infant birth weight and preterm birth.ResultsThe mean serum 25‐hydroxyvitamin D concentration in both maternal and cord blood was 37 ± 19 nmol/L with nearly 82% of mothers having vitamin D deficiency (25(OH)D <50 nmol/L). The mean birth weight of children born in this study was 2915 ± 431 grams with 13% of the children being classified as having low birth weight (<2,500 grams). Children born to women with serum vitamin D concentrations in the lowest quintile had significantly lower birth weight, compared to children born to women with vitamin D concentrations in the highest four quintiles (mean difference: 148 grams; 95% Confidence Interval: 45, 252 grams; p‐value <0.01).ConclusionsVitamin D deficiency is present in four out of five pregnant women in our cohort in an urban tropical setting and is associated with adverse birth outcomes such as lower birth weight. Studies with longer follow‐up are urgently needed to determine impact of poor vitamin D status on functional outcomes during childhood, and if vitamin D supplementation should be a part of standard antenatal care.Support or Funding InformationDivision of Nutritional Sciences, Cornell University