Maternal obesity and vitamin D sufficiency are associated with cord blood vitamin D insufficiency

Abstract

Context: An inverse relationship between total serum 25-hydroxyvitamin D (25-OH D) and increased adiposity has been established in children, adolescents, and adults. However, the relationship between neonatal adiposity and vitamin D status has not been reported. Both maternal obesity and vitamin D deficiency in pregnancy are common and are associated with adverse pregnancy outcomes.

Objective: The aim of the study was to determine the relationship between vitamin D levels in mothers and newborns, as influenced by maternal obesity, and evaluate these associations with neonatal adiposity.

Design, setting, and patients: Sixty-one maternal-neonatal pairs participated in this cross-sectional study at an academic medical center. Mothers had a prepregnancy body mass index that was normal or obese.

Outcome measures: Maternal and cord blood sera were assayed for 25-OH D, and neonatal body composition was measured by air displacement plethysmography.

Results: Mothers had similar and sufficient levels of 25-OH D when measured at 36-38 wk gestation, irrespective of body mass index category (normal weight, 46.05, vs. obese, 49.84 ng/ml; P = not significant). However, cord blood 25-OH D was higher in neonates of normal-weight mothers compared to neonates of obese mothers (27.45 vs. 20.81 ng/ml; P = 0.02). The variance in cord blood 25-OH D was explained by four factors: maternal 25-OH D level, the presence of maternal obesity, maternal age, and neonatal adiposity (r(2) = 0.66).

Conclusion: Obese women transfer less 25-OH D to offspring than normal-weight women, despite similar serum levels. Cord blood 25-OH D levels directly correlate to neonatal percentage body fat. These novel findings underscore the evolving relationships between maternal obesity, vitamin D nutritional status, and adiposity in the neonatal period that may influence subsequent childhood and adulthood vitamin D-dependent processes.

Fig. 1.

Normal-weight mothers and obese mothers had similar levels of 25-OH D measured at the end of pregnancy: 46.05 ± 2.96 vs. 49.84 ± 5.96 ng/ml (mean ± se), P = not significant. Filled bars, Maternal 25-OH D; hatched bars, cord blood 25-OH D. *, Cord blood levels of 25-OH D in neonates born to normal-weight vs. obese mothers were significantly different: 27.45 ± 1.69 vs. 20.81 ± 2.33 ng/ml; P = 0.02.