According to a new US study increased vitamin D levels of mothers at a gestation of 26 weeks or less may be related to a higher birth weight and a larger head circumference.
In the observational study, blood vitamin D concentrations of 2,146 pregnant women were measured at 26 weeks of gestation or less (1). Birth weight, head circumference, and placental weight were measured within 24 hours of birth. The study results showed that mothers with 25(OH)D levels above 15 ng/ml gave birth to newborns who weighed a mean 46 grams heavier and with head circumferences 0.13 cm larger than infants born from mothers who had a vitamin D status below 15 ng/ml. Birth weight and head circumference rose with increasing 25(OH)D up to 15 ng/ml and then leveled off.
The researchers concluded that maternal vitamin D status seems to be independently associated with mar-kers of growth in term infants. Large randomized controlled trials are needed to test whether maternal vitamin D supplementation may improve fetal growth. Previous studies have shown inconsistent associations between maternal vitamin D status and fetal size.