Maternal vitamin D supplementation during pregnancy prevents vitamin D deficiency in the newborn: an open-label randomized controlled trial

ObjectiveTo determine whether maternal vitamin D supplementation, in the vitamin D deficient mother, prevents neonatal vitamin D deficiency. DesignOpen-label randomized controlled trial. SettingMetropolitan Melbourne, Australia, tertiary hospital routine antenatal outpatient clinic. ParticipantsSeventy-eight women with singleton pregnancies with vitamin D deficiency/insufficiency (serum 25-OH Vit D<75nmol/l) at their first antenatal appointment at 12-16-week gestation were recruited. InterventionParticipants were randomized to vitamin D supplementation (2000-4000IUcholecalciferol) orally daily until delivery or no supplementation. Main outcome measuresThe primary outcome was neonatal serum 25-OH vit D concentration at delivery. The secondary outcome was maternal serum 25-OH vit D concentration at delivery. ResultsBaseline mean maternal serum 25-OH vit D concentrations were similar (P=09) between treatment (32nmol/l, 95% confidence interval 26-39nmol/l) and control groups (33nmol/l, 95% CI 26-39nmol/l). Umbilical cord serum 25-OH vit D concentrations at delivery were higher (P<00001) in neonates of treatment group mothers (81nmol/l, 95% CI; 70-91nmol/l) compared with neonates of control group mothers (42nmol/l, 95% CI; 34-50nmol/l) with a strongly positive correlation between maternal serum 25-OH Vit D and umbilical cord serum 25-OH vit D concentrations at delivery (Spearman rank correlation coefficient 088; P<00001). Mean maternal serum 25-OH Vit D concentrations at delivery were higher (P<00001) in the treatment group (71nmol/l, 95% CI; 62-81nmol/l) compared with the control group (36nmol/l, 95% CI; 29-42nmol/l). ConclusionVitamin D supplementation of vitamin D deficient pregnant women prevents neonatal vitamin D deficiency.