Effect of vitamin D supplementation during pregnancy on neonatal mineral homeostasis and anthropometry of the newborn and infant

Hypovitaminosis D is common in India. In the present prospective partially randomised study of vitamin D (D-3) supplementation during pregnancy, subjects were randomised in the second trimester to receive either one oral dose of 1500 mu g vitamin D-3 (group 1, n 48) or two doses of 3000 mg vitamin D-3 each in the second and third trimesters (group 2, n 49). Maternal 25-hydroxyvitamin D (25(OH) D) at term, cord blood (CB) alkaline phosphatase (ALP), neonatal serum Ca and anthropometry were measured in these subjects and in forty-three non-supplemented mother-infant pairs (usual care). Median maternal 25(OH) D at term was higher in group 2 (58.7, interquartile range (IQR) 38.4-89.4 nmol/l) v. group 1 (26.2, IQR 17.7-57.7 nmol/l) and usual-care group (39.2, IQR 21.2-73.4 nmol/l) (P=0.000). CB ALP was increased (> 8.02 mu kat/l or >480 IU/l) in 66.7% of the usual-care group v. 41.9% of group 1 and 38.9% of group 2 (P=0.03). Neonatal Ca and CB 25(OH) D did not differ significantly in the three groups. Birth weight, length and head circumference were greater and the anterior fontanelle was smaller in groups 1 and 2 (3.08 and 3.03 kg, 50.3 and 50.1 cm, 34.5 and 34.4 cm, 2.6 and 2.5 cm, respectively) v. usual care (2.77 kg, 49.4, 33.6, 3.3 cm; P=0.000 for length, head circumference and fontanelle and P=0.003 for weight). These differences were still evident at 9 months. We conclude that both 1500 mu g and two doses of 3000 mu g vitamin D-3 had a beneficial effect on infant anthropometry, the larger dose also improving CB ALP and maternal 25(OH)D.