Maternal vitamin D status of adolescent mothers at mid‐pregnancy influence bone mineral content of their newborns

We evaluated the effect of maternal vitamin D status at mid‐pregnancy, and of calcium plus vitamin D supplementation during the second half of pregnancy, on bone measurements of the newborn of Brazilian adolescent mothers (13–18y, n=26). Mothers were randomly assigned to receive daily Ca+vitD 3 supplement (600mg + 200UI, n=17) or placebo (n=9). Maternal serum 25OHD was measured by chemiluminescence immunoassay at 22–29 wk of pregnancy (65 ± 22 nmol/L) and at 3–6 wk postpartum (57 ± 26 nmol/L). Newborn (3–6wk) total bone mineral content (TBMC), density (TBMD) and bone area (TBA) were assessed by DXA. 25OHD decrease from mid‐pregnancy to postpartum (Δ) was lower in supplemented compared to placebo (Δ = −0.77 vs Δ = −20.6 nmol/L, respectively, P =0.04). Supplementation did not influence newborn bone measurements. However, after adjustment for maternal menarcheal age, maternal height, season and supplementation, newborns whose mothers had mid‐pregnancy 25OHD above or equal the median (≥66.9nmo/L) had 23% higher TBMC ( P =0.03) and TBA ( P =0.04) than those whose mothers had 25OHD below the median. Our results suggest that a combined Ca/VitD supplementation during pregnancy contributes to maintain a better maternal vitamin D status at early lactation, and indicate that vitamin D status of adolescent mothers at mid‐pregnancy influence bone mineral content of their newborns. Financial support: CNPq, FAPERJ (Brazil).