Cord Blood Vitamin D Status and Neonatal Outcomes in a Birth Cohort in Quebec

Abstract

Vitamin D status is assessed with circulating 25-hydroxyvitamin D [25(OH)D]. As some evidence suggests that low vitamin D status adversely affects neonatal health,

this project aimed to determine the association between cord blood 25(OH)D levels and preterm birth (PTB; <37 weeks gestation), low birthweight (LBW; <2500 grams) and small for gestational age (SGA; <10th percentile) and to examine the relationship between maternal 25(OH)D levels during the first trimester of pregnancy and fetal 25(OH)D levels at birth in a Canadian population. This nested case-control study used serums, questionnaires and chart reviews collected in Quebec City. Compared to 25(OH)D concentrations ≥75 nmol/L, concentrations 37.5-<75, 50-<75, and <75 nmol/L were associated with lower odds of LBW, PTB and an adverse neonatal composite outcome, and PTB as well as LBW, respectively. Maternal and neonatal 25(OH)D were correlated (r=0.23, p<0.01; adjusted r=0.46, p<0.01). This study contributes to evidence for identifying further policy and research directions.