IRCT201407115623N23 IRCT 2014-07-21 Arak University of Medical Sciences Effect of supplementation in treatment of gestational diabetes Effect of vitamin D plus calcium co-supplementation on pregnancy outcomes in gestational diabetes 2014-02-04 anticipated 60 Complete https://irct.ir/trial/6053 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Used, Assignment: Parallel, Purpose: Treatment, Randomization description: At study baseline and after stratification for pre-intervention BMI and weeks of gestation, subjects will be randomly divided into two groups to take either vitamin D plus calcium supplements (n = 30) or placebo (n = 30). Randomization will be done by the use of computer-generated random numbers, Blinding description: Randomization and allocation will be concealed from the researchers and participants until the final analyses are completed. Another person at the maternity clinics affiliated to Arak University of Medical Sciences, who is not involved in the trial and not aware of random sequences, will be assigned the participants to the numbered bottles of capsules. 2 Gestational diabetes. Intervention 1: Intervention group: Vitamin D3 capsule, 50000 IU, every 3 weeks for 6 weeks orally. Intervention 2: Intervention group: Calcium tablet, 500 mg, two times a day for 6 weeks orally. Intervention 3: Control group: Placebo capsule, every 3 weeks for 6 weeks orally. Intervention 4: Control group: Placebo tablet, two times a day for 6 weeks orally. Undecided - It is not yet known if there will be a plan to make this available Justification or reason for indecision in sharing IPD is Undecided - It is not yet known if there will be a plan to make this available