Purpose Several studies have reported increased risk of preeclampsia when 25-hyrdoxyvitamin D (25[OH]D) levels are low. and preeclampsia. For each 25 nmol/L increase in 25(OH)D the adjusted odds ratio for preeclampsia was 1.14 (95% confidence interval: 0.77 1.67 By contrast and contrary to hypothesis higher 25(OH)D concentrations were associated with higher odds of gestational hypertension: adjusted odds ratio for gestational hypertension was Erlotinib Hydrochloride 1.32 (95% confidence interval: 1.01 1.72 per each 25nmol/L increment in 25(OH)D. Vitamin D intake patterns suggest this association was not because of reverse causation. While the elevated hypertension risk may be due to chance randomized trials of vitamin D supplementation during pregnancy should monitor for gestational hypertension. Conclusions These data do not support the hypothesis that higher 25(OH)D levels lower the Rabbit polyclonal to FLT3. overall risk of hypertensive disorders of pregnancy. MeSH headings: Pregnancy Pre-Eclampsia Hypertension Pregnancy-Induced Vitamin D 25 D INTRODUCTION Beyond its well-established role in bone health vitamin D has been studied as a potentially modifiable factor contributing to extraskeletal health during pregnancy(1). During pregnancy vitamin D may play a role in implantation and placental function potentially due to angiogenic immunomodulatory and anti-inflammatory effects(2). While still incompletely comprehended the pathophysiology of preeclampsia likely involves abnormal placentation and angiogenesis (3). Several studies have exhibited an association between higher 25-hydroxyvitamin D (25[OH]D) levels in pregnancy and reduced risk of preeclampsia(4-9) especially severe preeclampsia(4 5 8 The National Institutes of Health has funded several ongoing trials to assess the extent to which vitamin Erlotinib Hydrochloride D supplementation during pregnancy may prevent perinatal complications(10). However vitamin D supplementation may not be without risk. In a study of dietary intake of several micronutrients we observed a potential increased risk of Erlotinib Hydrochloride gestational hypertension with higher dietary intakes of vitamin D during pregnancy (adjusted OR 1.11 95 1.01 1.21 per 100 IU of dietary vitamin D(11). In that earlier analysis however we did not have access to plasma 25(OH)D concentrations a better estimate of vitamin D status because 25(OH)D includes vitamin D from both diet and sun exposure. Our objective in this paper is usually to determine the extent to which plasma 25(OH)D concentrations during pregnancy are associated with hypertensive disorders of pregnancy namely preeclampsia and gestational hypertension. MATERIALS and METHODS We studied women participating in Project Viva a prospective prenatal cohort study in Massachusetts. We recruited women who were attending their initial prenatal visit (mean 10.5 weeks gestation) at one of 8 urban and suburban obstetrical offices of Harvard Vanguard Medical Associations a multi-specialty group practice located in eastern Massachusetts. Women provided written informed consent. Details of cohort recruitment and retention are published elsewhere(12). Of the 2128 participants who delivered live infants we classified 28 women as chronically hypertensive (defined as taking antihypertensive medications or with two elevated clinically measured Erlotinib Hydrochloride blood pressure values [systolic (SBP) >140 mm Hg or diastolic (DBP) >90 mm Hg] before 20 weeks gestation) and excluded them from all analyses. Of the 2100 remaining we obtained plasma samples from 1591 at the time of the routine blood collection to screen for gestational diabetes (mean 27.9 weeks gestation; range 16.4-36.9 weeks). All had assessments of hypertensive outcomes. The institutional review boards of participating institutions approved the study. Blood samples were initially refrigerated and then we separated the plasma and stored aliquots at ?80°C. We analyzed each sample Erlotinib Hydrochloride in duplicate for 25(OH)D concentration once using an automated chemiluminescence immunoassay (13) and once using a manual radioimmunoassay (r=0.81)(14). As Erlotinib Hydrochloride we have done in prior studies we averaged the two values to obtain more stable.