Prenatal vitamin D supplementation may be unable to fight gestational diabetes

Vitamin D deficiency is a common health problem among both children and adults worldwide, and has often been associated with increased diabetes risk.

Researchers from the Isfahan University of Medical Sciences therefore aimed to determine if vitamin D supplementation would have any impact on the incidence of gestational diabetes in pregnant women.

They conducted a one-year RCT on 210 pregnant women aged 16 to 36, whom they randomly divided into three groups: one with normal vitamin D levels, and two with insufficient vitamin D levels.

Statistical significance​

Participants in one of the vitamin D-deficient groups were administered 50,000 IU of vitamin D supplementation every fortnight for 10 weeks, while participants in the other vitamin D-deficient group received omega-3 pearl as a placebo.

The incidence of gestational diabetes was then measured in all three groups after 24 to 26 weeks of pregnancy.

The incidence of the disease was 8.57% in the group with normal vitamin D levels, 10% in the vitamin D-supplemented group, and 11.43% in the placebo group.

Based on these findings, the study asserted that the difference between the three groups in terms of gestational diabetes incidence was “not statistically significant”​.

Contradictions and disagreements​

Several earlier studies on the relationship between vitamin D status and gestational diabetes have pointed to vitamin D supplementation as useful in lowering the risk of the disease.

Most of such studies reported an “inverse relationship between circulating vitamin D levels and markers of glucose homeostasis…or an increased risk for gestational diabetes mellitus, associated with reduced maternal levels of vitamin D between 24 and 30 weeks of gestation”​.

Higher vitamin D levels were also associated with lower levels of insulin and fasting glucose.

While some studies deemed it unnecessary, others recommended up to 2000 IU of vitamin D supplementation a day. But even with supplementation, “only a small percentage of women and babies were vitamin D-sufficient”​.

Results may vary​

The study also pointed out that differing genetic and environmental factors meant that the results of vitamin D supplementation could vary from one person to another.

It said that despite the statistically insignificant differences in results among the three groups, whether or not vitamin D supplementation can prevent gestational diabetes (in a cost-effective method) is still unclear.

As such, it concluded that “future studies on the cost-effectiveness of the use of these supplements during pregnancy (should) be conducted”​.

Source: Advanced Biomedical Research​

Volume 6

“Effect of Vitamin D Supplementation on the Incidence of Gestational Diabetes”​

Authors: Hatav Ghasemi Tehrani, Fatemeh Mostajeran,  Behnaz Banihashemi