Selenium supplementation for management of gestational diabetes mellitus in pregnancy: a systematic review and meta-analysis of randomized controlled trials.

Background: Selenium is thought to improve glucose and lipid metabolism in pregnant women with gestational diabetes mellitus. However, this finding is somewhat controversial. In this paper, we evaluated the effects of selenium supplementation on glucose and lipid metabolism in patients with GDM.

Methods: Searches were carried out in PubMed, Cochrane Library, Web of Science, EMBASE, CBM, Chinese National Knowledge Infrastructure, Wan Fang, and VIP from their inception until May 2025. Two reviewers independently extracted data. The Cochrane risk of bias tool was applied to assess the methodological quality of every study and Meta-analysis was carried out with a random effects model or a fixed effects model. Publication bias was evaluated by the Begg and Egger tests.

Results: Four randomized controlled trials, with 230 participants in total, were included. Participants were between 18 and 45 years old. The time span of these studies ranged from 2015 to 2022. The daily dose of selenium supplementation was from 100 µg/d to 200 µg/d and the duration of intervention was 6 weeks to 12 weeks. Compared with placebo group, the selenium group did not significantly reduce the level of homeostasis model assessment of insulin resistance(P = 0.20, MD = -0.71, 95%CI: -1.80, 0.37). Selenium supplementation at 200 µg/d significantly reduced fasting plasma glucose(P = 0.0002, MD = -5.03, 95% CI: -7.70, -2.37) and the incidence of newborn's hyperbilirubinemia((P = 0.0003, MD = 0.09, 95% CI: 0.03, 0.33). However, there was no obvious differences in improving total cholesterol, triglycerides, low density lipoprotein cholesterol and high density lipoprotein cholesterol.

Conclusions: For pregnant women with gestational diabetes mellitus, daily supplementation with 200 µg of selenium may help lower fasting blood glucose levels and the risk of hyperbilirubinemia in the newborn, but it does not significantly affect total cholesterol, triglycerides, low density lipoprotein cholesterol, or high density lipoprotein cholesterol levels. Given the limitations of this study, these conclusions require further validation.