Maternal vitamin D supplementation in pregnancy and offspring outcomes: a double-blind randomized placebo-controlled...

We studied bone mineral content (BMC), bone mineral density (BMD), and body composition in offspring of women supplemented with vitamin D during pregnancy. Pregnant women were randomized to receive oral cholecalciferol 60,000 units 4 weekly (group 1), 8 weekly (group 2), or placebo (group 3). All received 1 g calcium daily (groups 1 and 2 without, and group 3 with 400 units vitamin D). Offspring at 12-16 months underwent dual-energy X-ray absorptiometry. Maternal hypovitaminosis D at recruitment was common (serum 25OHD <50 nmol/L in 88 %) and severe (25OHD <25 nmol/L in 46 %). Groups 1 and 2 (n = 23 and 13, median age 14 months) had higher cord blood 25OHD (47.8 ± 13.8 and 31.0 ± 14.0 nmol/L) versus group 3 (n = 16, median age 16 months, 17.8 ± 13.5 nmol/L, p < 0.001). Babies in group 3 had higher whole-body BMC (250.8 ± 42.5 gm) and BMD (0.335 ± 0.033 gm/cm²) compared to group 1 (213.1 ± 46.2 gm and 0.295 ± 0.041 gm/cm²) and group 2 (202.9 ± 29.9 gm and 0.287 ± 0.023 gm/cm²) (p = 0.006 and 0.001, respectively). In multivariate analysis, age, weight z score, and lean body mass remained significant contributors to BMC. Parameters of body composition were comparable among the groups. Vitamin D supplementation to pregnant women with severe deficiency in doses that improved cord blood 25OHD did not result in improved bone health or body composition in offspring at 12-16 months, compared to a dose too small to improve 25OHD levels.