IRCT201306253140N11 IRCT 2013-07-05 Vice chancellor for Research, Tabriz University of Medical Sciences Effect of vitamin D supplementation in the treatment of patients with gestational diabetes Effect of vitamin D supplementation on serum vitamin D levels and markers of metabolic and inflammatory in women with gestational diabetes 2013-06-22 anticipated 90 Complete https://irct.ir/trial/3179 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Used, Assignment: Parallel, Purpose: Treatment. N/A Gestational diabetes mellitus. Intervention 1: Intervention group will receive 4 oral vitamin D supplement capsules consisting of 50000 IU of vitamin D3 ) 1 every 2 weeks for 8 weeks. Vitamin D supplements will be purchased from the Zahravi Pharm Co. All the patients will receive the supplement on every two weeks base and will be monitored for consumption continuation and any possible adverse effects by telephone interviews. Intervention 2: The control group received 4 oral placebo (containing paraffin) 1 every 2 weeks for 8 weeks. Vitamin D supplements will be purchased from the Zahravi Pharm Co. All the patients will receive the supplement on every two weeks base and will be monitored for consumption continuation and any possible adverse effects by telephone interviews.