Effect of probiotics on pregnancy outcomes in gestational diabetes: systematic review and meta-analysis

Objective: Gestational diabetes mellitus (GDM) is a prevalent complication during pregnancy associated with numerous adverse outcomes. There is emerging evidence suggesting the potential of probiotics as a therapeutic measure for GDM; however, existing studies have yielded contradictory results. This meta-analysis assessed the efficacy of probiotics on blood glucose management and pregnancy outcomes in patients with GDM. Methods: A comprehensive search of the PubMed, Embase, and Cochrane databases was conducted up to August 22, 2023, to identify relevant studies. The primary outcomes focused on fasting blood glucose (FBG), fasting serum insulin (FSI), homeostasis model assessment of insulin resistance (HOMA-IR), and quantitative insulin sensitivity check index (QUICKI). The secondary outcomes included various maternal and neonatal outcomes. Results: This meta-analysis included 15 randomized controlled trials (RCTs), encompassing 1006 patients with GDM. The results showed that, compared to a placebo, probiotics demonstrated a significant reduction in FBG (MD - 2.58, 95% CI - 4.38 to - 0.79, p < 0.01), FSI (MD - 2.29, 95% CI - 3.40 to - 1.18, p < 0.01), HOMA-IR (MD - 0.56, 95% CI - 0.81 to - 0.32, p < 0.01), and birth weight (MD - 101.20, 95% CI - 184.62 to - 17.77, p = 0.02). Furthermore, it resulted in fewer neonatal intensive care unit (NICU) admissions (RR 0.60, 95% CI 0.40-0.89, p = 0.01), instances of hyperbilirubinemia (RR 0.31, 95% CI 0.16-0.61, p < 0.01), and elevated QUICKI (MD 0.01, 95% CI 0.00-0.01, p < 0.01). No significant impact was observed in the other analyzed outcomes. Conclusions: In conclusion, probiotics improve FBG, FSI, and HOMA-IR, and reduce the occurrence of neonatal hyperbilirubinemia, NICU admissions, and birth weight in the offspring of patients with GDM. However, the quality of the evidence, as per the GRADE approach, varies from high to low, necessitating further studies to consolidate these findings.