Maternal Serum Vitamin D Level and Its Association with Preeclampsia

Open Access

Abstract

Background: Preeclampsia is a pregnancy specific hypertensive disorder with multi-system involvement, usually occurs after 20 weeks of gestation. Vitamin D insufficiency is highly prevalent in children and adults including pregnant women. During pregnancy, maternal vitamin D insufficiency could increase risks of several pregnancy complications and adverse birth outcomes. Objectives: The aim of the study was to evaluate the vitamin D levels in preeclamptic and normotensive pregnant women and the role of vitamin D deficiency in the etiology of preeclampsia. Methods & Materials: In this case-control study, 50 preeclamptic women and 50 normotensive pregnant women were selected from Obstetrics & Gynecology department of Chittagong Medical College Hospital in Chattogram, Bangladesh by convenient sampling technique. Two ml of venous blood sample was collected from each pregnant woman and the serum 25-OH-D level was measured by Chemiluminescent Microparticle Immunoassay method and reported in nanograms per milliliter. levels of 25-OH-D less than 20 ng/mL, between 20 ng/mL and 29 ng/mL and more than 30 ng/mL, were considered as deficient, insufficient and sufficient 25-OH-D concentrations, respectively. Results were analyzed by independent t-test, Mann-Whitney U test, Chi-square test, Fisher’s exact test, and logistic regression. Results: Out of 50 preeclamptic cases, 28 (56.0%) had preeclampsia with severe features, and 22 (44.0%) had preeclampsia without severe features. The median serum vitamin D level of women with preeclampsia with severe features, preeclampsia without severe features and normotensive women were respectively 10.5 ng/ml, 11.9 ng/ml, and 17.5 ng/ml. This difference was highly significant statistically (p <0.001). Pairwise comparison between groups showed that preeclampsia with severe features and preeclampsia without severe features had significantly lower vitamin D levels than normotensive women, but the difference between the preeclampsia without severe features group and preeclampsia with severe features group was not statistically significant (p=0.420). The majority of the cases (92.0%) had a low vitamin D level compared to 58.0% of control group (p <0.001). Only one (2.0%) and 2 (4.0%) in cases and control groups respectively had adequate vitamin D levels in their serum (p=1.0). Participants with vitamin D deficiency had a statistically non-significant higher odd for preeclampsia (OR= 1.11, 95% CI = 0.05-24.51, p=0.946), compared to normotensive pregnant women. Conclusions: The prevalence of vitamin D deficiency was high in both normotensive pregnancies and pregnancies complicated by preeclampsia but amplified in preeclampsia. Additional studies are needed to explore the potential benefits and optimal dosing of vitamin D use in pregnancy.