Effect of Vitamin D Supplementation for Obese Pregnant Women on Gestational Diabetes and Diabetes Biomarkers

Background: High rates of vitamin D deficiency in Jordan are alarming especially when they are associated with obesity during pregnancy.

Objectives: To investigate the effect of vitamin D supplementation for obese pregnant women on gestational diabetes and diabetes biomarkers.

Methods: 118 women were investigated and were divided into three groups. Each group was divided into two treatment subgroups. (1) Women (n=23) with normal 25(OH)D levels were given either no supplementation (1A=12) or given vitamin D supplementation of 10000 IU/wk (1B=11), (2) women (n=43) with insufficient 25(OH)D levels were given either 10000 IU/wk (2A= 22) or 20000 IU/wk of vitamin D supplementation (2B=21), (3) women of group 3 (n=52) with deficient 25(OH)D levels were given either 20000 IU/wk (3A=26) or 50000 IU/wk (3B=26) of vitamin D supplementation.

Results: Fasting blood sugar showed decreased levels among B treatment subgroups in both group 1 and 3, while no significant difference was found between A and B treatment subgroups in group 2. Insulin resistance showed a significant difference between A and B treatment subgroups among group 2 and 3 but not group 1.

Conclusion: Screening for 25(OH)D during pregnancy and appropriate replacement, especially in patients with severe deficiency, may contribute to the prevention of gestational diabetes mellitus.