Maternal vitamin D status in pregnancy and adverse pregnancy outcomes in a group at high risk for pre-eclampsia

Objective: To determine in a group of pregnant women if vitamin D status, based on serum 25-hydroxyvitamin D (25OHD) concentration, was associated with a subsequent risk of pre-eclampsia or adverse pregnancy outcomes. 

Design: Prospective cohort study. Setting Vancouver, British Columbia, Canada (49°N). Population Women attending a specialist antenatal clinic because of clinical or biochemical risk factors for pre-eclampsia (n=221). 

Methods: Serum 25OHD concentration measured between 10 and 20weeks of gestation. Main outcome measures Pre-eclampsia and composite adverse pregnancy outcomes. Results Of the women, 78% were vitamin D insufficient (25OHD <75nmol/l) and 53% were vitamin D deficient (25OHD <50nmol/l). There was no difference in the rates of pre-eclampsia, gestational hypertension, preterm birth or composite adverse pregnancy outcomes by 25OHD concentration. 

Conclusions: Vitamin D deficiency and insufficiency were common in a group of women at high risk of pre-eclampsia; however, it was not associated with subsequent risk of an adverse pregnancy outcome.