Maternal Metabolic Management in Gestational Diabetes Mellitus: Intersecting Effects of Ramadan Fasting and Vitamin D Supplementation

Background: Gestational diabetes mellitus (GDM) and pre existing diabetes during pregnancy pose significant metabolic challenges requiring carefully tailored management strategies. Two clinically relevant but under explored areas include the effectiveness of high dose vitamin D supplementation in GDM and the feasibility of Ramadan fasting among pregnant women with diabetes treated with insulin. Methods: This narrative review synthesized findings from two primary clinical studies that investigated: (۱) the metabolic and biochemical effects of a single high dose intramuscular vitamin D injection (۳۰۰,۰۰۰ IU) in women with GDM, and (۲) the metabolic safety and feasibility of Ramadan fasting in pregnant diabetic women on insulin therapy. A structured literature search up to December ۲۰۲۵ was conducted to contextualize the evidence; however, data extraction and detailed analysis were based exclusively on the two included studies. Results: High dose vitamin D supplementation markedly improved serum ۲۵(OH)D concentrations, reducing deficiency prevalence from approximately ۸۰% to ۴% and producing significant decreases in parathyroid hormone levels without inducing hypercalcemia, demonstrating both biochemical efficacy and safety. The study on Ramadan fasting showed that pregnant women with GDM or type ۲ diabetes, under supervised insulin therapy, could fast for a mean of ۲۵ days without experiencing hypoglycemia. Glycemic indices improved modestly, including reductions in HbA۱c and fructosamine, suggesting that fasting may be metabolically feasible when accompanied by close monitoring and individualized insulin adjustments. Conclusion: Evidence from these two focused clinical investigations indicates that both high dose vitamin D supplementation and supervised Ramadan fasting may serve as safe and potentially beneficial components of metabolic management in diabetic pregnancy. Vitamin D megadose therapy effectively corrects deficiency and improves biochemical markers, whereas Ramadan fasting when medically supervised appears feasible without compromising glycemic stability. Further large scale, controlled studies are warranted to validate these findings and guide practice recommendations.

کلیدواژه ها:

Gestational diabetes mellitus ، Vitamin D supplementation ، High dose vitamin D ، Ramadan fasting ، Pregnant women with diabetes ، Insulin therapy ، Glycemic control ، ۲۵ hydroxyvitamin D ، Parathyroid hormone ، Maternal metabolic management