Mahdieh Mojibian - Department of Obstetrics andGynecology, Shahid Sadoughi Hospital, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
Sedigheh Soheilykhah - ۲. Department of Endocrine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
Mohammad Ali Fallah Zadeh - Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Maryam Jannati Moghadam - Department of Obstetrics and Gynecology, Mojibian Hospital, Yazd, Iran.

Background: Vitamin D supplementation during pregnancy has been supposed to defend against adverse gestational outcomes.Objective: This randomized clinical trial study was conducted to assess the effects of 50,000 IU of vitamin D every two weeks supplementation on the incidence of gestational diabetes (GDM), gestational hypertension, preeclampsia and preterm labor, vitamin D status at term and neonatal outcomes contrasted with pregnant women that received 400 IU vitamin D daily.Materials and Methods: 500 women with gestational age 12-16 weeks and serum 25 hydroxy vitamin D (25 (OH) D ) less than 30 ng/ml randomly categorized in two groups. Group A received 400 IU vitamin D daily and group B 50,000 IU vitamin D every 2 weeks orally until delivery. Maternal and Neonatal outcomes were assessed in two groups.Results: The incidence of GDM in group B was significantly lower than group A (6.7% versus 13.4%) and odds ratio (95% Confidence interval) was 0.46 (0.24-0.87)(P=0.01). The mean ± SD level of 25 (OH) D at the time of delivery in mothers in group B was significantly higher than A (37.9 ± 19.8 versus 27.2 ± 18.8 ng/ml, respectively) (P=0.001). There were no differences in the incidence of preeclampsia, gestational hypertension, preterm labor, and low birth weight between two groups. The mean level of 25 (OH) D in cord blood of group B was significantly higher than group A (37.9 ± 18 versus 29.7 ± 19ng/ml, respectively). Anthropometric measures between neonates were not significantly different.Conclusion: Our study showed 50,000 IU vitamin D every 2 weeks decreased the incidence of GDM.

Vitamin D, Pregnancy outcome, Gestational diabetes