Association of newborn vitamin D status with pregnancy outcome and infant health

Abstract

There is little information available about the relationship of newborn vitamin D status with pregnancy outcome and infant health. The purpose of this cross-sectional study was to estimate the prevalence of vitamin D deficiency and insufficiency in newborns in the Saskatoon Health Region, identify risk factors for low neonatal levels of vitamin D, and determine whether any association exists between low levels of vitamin D and adverse pregnancy and neonatal outcomes. The Newborn Vitamin D Study was conducted between December, 2011 and February, 2012. Sixty-five maternal-fetal dyads delivering in the Saskatoon Health Region were included in the study. Mean cord blood vitamin D level was 64.1 nmol/L (standard deviation = 19.8 nmol/L), which is in the insufficient range. Cord blood vitamin D level was deficient (<50 nmol/L) in 22% and insufficient (50-75 nmol/L) in 48% of the 65 newborns studied. Simple linear regression indicated that low weight gain during pregnancy is significantly associated with low vitamin D levels (p = 0.04). However, younger maternal age (p < 0.01) and urban area of residence (p = 0.09) were the strongest predictors of low cord blood vitamin D levels in a multiple linear regression model (R2 of 0.519, p = 0.003). Cord blood vitamin D levels were not significantly associated with any pregnancy or neonatal outcomes. Despite 85% of mothers reporting having taken a daily prenatal supplement, 70% of newborns in our study population had either an insufficient or deficient cord blood vitamin D status. This suggests that prenatal supplements, which typically contain 400 IU of vitamin D, contain an inadequate dose of vitamin D to produce sufficient cord blood vitamin D levels in most newborns. Further research is necessary to inform maternal vitamin D supplementation guidelines and to investigate the role of vitamin D in pregnancy outcomes and infant health.