[Factors associated with the prevalence of hypovitaminosis D in pregnant women and their newborns].

Background: The finding of hypovitaminosis in pregnancy D has prompted the debate about its supplementation. The objective of the study was to measure the prevalence of hypovitaminosis D in mothers and newborns.

Methods: A one-year observational study was conducted including the measuring of vitamin D levels in mothers and in the umbilical cord blood of newborns. An analysis was made of the variables as regards maternal characteristics, delivery and sun exposure.

Results: Values lower than 20 ng/ml were found in 64.4% of 745 mothers and 41.3% of 560 newborns, and less than 30 ng/ml in 88.7% and 67.1%, respectively. Mean levels were higher in summer-autumn than in winter-spring (21.73 and 13.70 ng / ml in mothers and 29.04 and 20.49 ng/ml in cord), and higher in the umbilical cord than in the maternal plasma. Multiple pregnancies (OR: 6.29) and non-European origin (OR: 13.09) were risk factors for maternal hypovitaminosis, while maternal supplementation (OR: 0.19), physical activity (OR: 0.57), and sun exposure (OR: 0.46) had a preventive effect.

Conclusions: The high rates of hypovitaminosis support the policy of giving dietary supplements to newborns. The high level of hypovitaminosis found supports the extension of screening and supplementation to all pregnant women, and not only to those with risk factors. The greater difference between mothers and newborns in seasons of low sun exposure can be interpreted as a protective effect.