IRCT201605135623N78 IRCT 2016-05-21 Vice chancellor for research, Arak University of Medical Sciences Effect of supplementation in treatment of patients with gestational diabetes Clinical trial of the effect of combined omega-3 fatty acids and vitamin D supplementation compared with the placebo on metabolic profiles in patients with gestational diabetes 2016-03-06 anticipated 140 Complete https://irct.ir/trial/6108 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Used, Assignment: Parallel, Purpose: Treatment, Randomization description: 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 Clinic who is not involved in the trial and not aware of random sequences will allocate the numbered bottles of capsules to participants. Supplements and placebo are in the same packaging at the pharmaceutical company. Only the code is written on the packages. Patients and researcher do not know the type of drug and after analyzing the data, packet codes are decoded. 3 Gestational diabetes. Intervention 1: Control group: Placebo (Zahravi, Tabriz, Iran), for 6 weeks orally. Intervention 2: Intervention group 1: Combined 1000 mg omega-3 fatty acids twice a day (Zahravi, Tabriz, Iran) and 50000 IU vitamin D every 2 weeks (Zahravi, Tabriz, Iran), for 6 weeks orally. Intervention 3: Intervention group 2: 1000 mg omega-3 fatty acids (Zahravi, Tabriz, Iran), twice a day, for 6 weeks orally. Intervention 4: Intervention group 3: 50000 IU vitamin D every 2 weeks (Zahravi, Tabriz, Iran), 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.