The Impact of Vitamin D Supplementation on Post-Partum Glucose Tolerance and Insulin Resistance in Gestational Diabetes: A Randomized Controlled Trial

Hypovitaminosis D has been associated with the development of gestational diabetes mellitus (GDM) in many observational studies..
We report the first study of the impact of prenatal vitamin D supplementation on postpartum dysglycemia in GDM patients in a randomized clinical trial..
Patients and Women with GDM at 12 - 32 weeks of gestation were assigned randomly to either the intervention group (in which serum 25-hydroxy vitamin D [25OHD] levels were measured immediately, n = 48) or the control group (in which the serum was stored and assayed at 6 - 12 weeks post-partum, n = 48). Participants with initial serum 25OHD The mean ± SD of serum 25OHD in the intervention group raised dramatically from 14.6 ± 6.3 to 32.4 ± 14.4 ng/mL, whereas no significant change occurred in the control group (from 17.7 ± 6.1 to 19.3 ± 9.6 ng/mL, P Although the high vitamin D supplementation dose in the present study (compared to the 400 IU/day dose usually recommended for pregnancy) safely increases the serum 25OHD, in GDM cases, the higher dose does not affect the plasma glucose level or insulin resistance at short term follow-up after delivery..