The effect of probiotics on gestational diabetes mellitus: an umbrella meta-analysis

Prior studies indicated the positive effects of probiotics on glycemic regulation in patients with gestational diabetes mellitus (GDM). Nonetheless, the results remain inconclusive. To address this, we conducted an umbrella meta-analysis to evaluate the impact of probiotics on glycemic indicators in GDM. A comprehensive search was conducted on the PubMed and Scopus databases to identify all relevant meta-analyses of randomized clinical trials published until July 2024. The outcomes included serum hemoglobin A1C (HbA1c), fasting blood insulin (FBI), fasting blood sugar (FBS), homeostatic model assessment for insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), homeostatic model assessment of beta cell function (HOMA-B), C-peptide, and oral glucose tolerance test (OGTT). Standardized mean difference (SMD) was used to test the effects. In total, 27 studies, comprising 33,378 participants, were included in the analysis. Probiotics resulted in a significant decrease in FBS (SMD: -0.39, 95% CI: -0.56 to -0.23), especially when administered for ≤ 7 weeks. Significant reductions were also observed in FBI (SMD: -1.99, 95% CI: -2.41 to -1.58), HOMA-IR (SMD: -0.61, 95% CI: -0.72 to -0.50), and HOMA-B (SMD: -24.58, 95% CI: -30.59 to -18.56). Moreover, supplementation with probiotics significantly improved QUICKI (SMD: 0.007, 95% CI: 0.004 to 0.01). There was significant evidence of heterogeneity and publication bias. No significant effects were observed on 1-h OGTT, 2-h OGTT, HbA1c, and C-peptide. No dose-specific effect was observed. Supplementation with probiotics could improve glycemic control in women with GDM. The effects of probiotics on HOMA-IR, HOMA-B, and fasting insulin were clinically important, while, their effect on FBS was not clinically important.