Elevated preeclampsia rates during winter with reduced sunlight dependent vitamin D production

Abstract

Title: Preeclampsia rates are elevated during winter month when sunlight dependent vitamin D production is reduced. Aim: To assess maternal vitamin D deficiency in early pregnancy and risk of preeclampsia. Settings and Design:Nested case control study. Two maternal blood sample, one at <20 wks and other at term along with cord blood at delivery were taken. Patients were classified into preeclampsia (n=57) and control group (n=178) after abstracting past medical records at delivery. Methods and Material: Vitamin D was estimated by 25-Hydroxyvitamin D 125 I RIA Kit and categorized according to ACOG (2011) criteria. Statistical analysis used: Pearson χ 2 , ANOVA and logistic regression were used. Linear correlation and regression coefficient was used between maternal 25(OH) D at <20 wks and term and cord serum 25(OH)D levels. Results: serum 25(OH)D concentrations in early pregnancy were 56% significantly lower in women who subsequently developed preeclampsia compared with controls (mean, 9.79 ± 4.09 ng/ml , 95% CI, 8.71-10.88 ng/ml, vs. 22.26 ± 15.28 ng/ml and, 95%CI, 20.0-24.52 ng/ml; P<0.001) independent of age, BMI, calcium intake, socioeconomic status, periconceptional multivitamin use, residence. There was 17 times increased risk of preeclampsia in vitamin D deficient mothers compared to controls at early pregnancy and at term. (P<0.001; rr =17.93). Newborns of preeclamptic mothers were more than three times as likely as newborns of controls to have hypovitaminosis D(relative risk 3.55). Conclusions: Maternal vitamin D deficiency is highly prevalent in early pregnancy and is an independent risk factor for preeclampsia.