Effect of vitamin D supplementation in the reduce risk of preeclampsia in nulliparous women

BACKGROUND: The exact role of vitamin D in the development and severity of preeclampsia is still unclear. The aim of the present study was to investigate the association between vitamin D supplement and preeclampsia in pregnant women. MATERIALS AND METHODS: In this randomized controlled trial, in 2012, 140 nulliparous pregnant women in two groups received supplementation with 600 IU/day of vitamin D or supplementation free of vitamin D at 16 week gestation until the delivery. The main outcomes included the frequency of preeclampsia and subtypes by clinical severity and infant birth weight. RESULTS: Mean of maternal age and gestational age at the delivery in all studied subjects were 25 ± 4.1 years and 37.4 ± 3 weeks, respectively, which were not statistically significant between the groups. Preeclampsia was observed in two subjects in case group compared to seven subjects in control group, which was not significant (P-value = 0.09). In case group, subjects with preeclampsia diagnosed as mild preeclampsia and in control group four subjects were mild, and three were severe. No significant differences were noted between the case and control groups in the frequency of preeclampsia subtypes by clinical severity. Infant birth weight in case group who was significantly higher than control group, which was statistically significant between groups (P-value = 0.09). CONCLUSION: In summary, our results demonstrated that vitamin D supplementation during the third trimester of pregnancy; despite the non-significant association between vitamin D supplementation and preeclampsia, reduce the risk of preeclampsia. However, further studies needs to be done.