The relationship between 25-hydroxyvitamin D concentration in early pregnancy and pregnancy outcomes in a large, prospective cohort

Vitamin D insufficiency and deficiency have been associated with an increased risk of adverse pregnancy outcomes. Controversy remains as findings have been inconsistent between disparate populations. The aim of this study was to investigate the relationship between vitamin D status and pregnancy outcomes in a large, prospective pregnancy cohort. 25-Hydroxyvitamin D concentration was analysed in serum samples collected at 15 weeks of gestation from 1710 New Zealand women participating in a large, observational study. Associations between vitamin D status and pre-eclampsia, preterm birth, small for gestational age (SGA) and gestational diabetes were investigated. The mean 25-hydroxyvitamin D concentration was 729 nmol/l. In all, 23 % had 25-hydroxyvitamin D concentrations amp;lt; 50 nmol/l, and 5 % of participants had concentrations amp;lt; 25 nmol/l. Women with 25-hydroxyvitamin D concentrations amp;lt; 75 nmol/l at 15 weeks of gestation were more likely to develop gestational diabetes mellitus than those with concentrations amp;gt; 75 nmol/l (OR 23; 95 % CI 11, 51). However, this effect was not significant when adjustments were made for BMI and ethnicity (OR 18; 95 % CI 08, 42). 25-Hydroxyvitamin D concentration at 15 weeks was not associated with development of pre-eclampsia, spontaneous preterm birth or SGA infants. Pregnancy complications were low in this largely vitamin D-replete population.Funding Agencies|Gravida via Uniservices, a Centre of Research Excellence of the NZ Government Tertiary Education Commission [33015.001]