Vitamin D during pregnancy and infancy and infant serum 25-hydroxyvitamin D concentration

Abstract

OBJECTIVE: To determine the vitamin D dose necessary to achieve serum 25-hydroxyvitamin D (25(OH)D) concentration ≥20 ng/mL during infancy. METHODS: A randomized, double-blind, placebo-controlled trial in New Zealand. Pregnant mothers, from 27 weeks' gestation to birth, and then their infants, from birth to age 6 months, were randomly assigned to 1 of 3 mother/infant groups: placebo/placebo, vitamin D3 1000/400 IU, or vitamin D 3 2000/800 IU. Serum 25(OH)D and calcium concentrations were measured at enrollment, 36 weeks' gestation, in cord blood, and in infants at 2, 4, and 6 months of age. RESULTS: Two-hundred-and-sixty pregnant women were randomized. At enrollment, the proportions with serum 25(OH)D ≥20 ng/mL for placebo, lower-dose, and higher-dose groups were 54%, 64%, and 55%, respectively. The proportion with 25(OH)D ≥20 ng/mL was larger in both intervention groups at 36 weeks' gestation (50%, 91%, 89%, P < .001), 2 months (50%, 82%, 92%, P