This meta-analysis sought to examine how magnesium supplementation impacts glycemic control and pregnancy outcomes among women battling gestational diabetes.

Multiple databases like Cochrane Library, EBSCO, Embase, PubMed, and Web of Science were systematically analyzed. Researchers focused on randomized controlled trials (RCTs) examining magnesium's effectiveness in gestational diabetes. Based on the presence of heterogeneity, the meta-analysis employed either the random-effect model or the fixed-effect model.

The study encompassed five RCTs involving 266 participants. Compared to control interventions for gestational diabetes, magnesium supplementation illustrated a profound drop in fasting plasma glucose (mean difference [MD] = -7.33 mg/dL; 95% confidence interval [CI] = -7.64 to −7.02 mg/dL; P < 0.00001) and homeostatic model assessment of insulin resistance (HOMA-IR) (MD = -0.99; 95% CI = -1.76 to −0.22; P = 0.01).

However, it revealed no substantial impact on serum insulin levels (MD = -4.17 μIU/mL; 95% CI = -8.49 to 0.14 μIU/mL; P = 0.06), macrosomia (OR = 0.34; 95% CI = 0.08 to 1.35; P = 0.13), preterm delivery (odds ratio [OR] = 0.42; 95% CI = 0.06 to 2.95; P = 0.38), or alterations in body mass index (MD = -0.01 kg/m2; 95% CI = -0.06 to 0.04 kg/m2; P = 0.63).

Magnesium supplementation substantially decreases fasting plasma glucose and HOMA-IR in gestational diabetes, but has no significant impact on serum insulin, preterm delivery, macrosomia, or body mass index change.