The Effect of Probiotics or Synbiotics on the Hypertensive Disorders of Pregnant Women with Gestational Diabetes: A Systematic Review and Meta-analysis.

Introduction: Antioxidants and anti-inflammatory drugs have been suggested to treat preeclampsia. This systematic review and meta-analysis was conducted to investigate the efficacy of probiotic or synbiotic supplementation on hypertensive disorders in women with gestational diabetes mellitus (GDM) . Methods: The databases including Cochrane, Embase, Ovid, ProQuest, Scopus, Web of Science, and PubMed were systematically searched for collecting the randomized controlled trials (RCTs) investigating the efficacy of probiotic or synbiotic supplementation versus placebo on hypertensive disorders and pregnancy outcomes in GDM until July 2020. Results: Five RCTs with a total sample size of 402 women were included in the meta-analysis. There was no significant decline in systolic blood pressure (standardized mean difference [SMD]=-3.41, 95% confidence interval [CI]=-8.32 to 1.50, P=0.17), diastolic blood pressure (SMD=-5.11, 95% CI=-14.20 to -3.98, P=0.27), preeclampsia (odds ratio [OR]=1.56, 95% CI=0.61 to 3.98, P=0.35), cesarean section (OR=0.52, 95% CI=0.18 to 1.50, P=0.23), and macrosomia (OR=0.81, 95% CI=0.41 to 1.57, P=0.53). No significant increase was observed in terms of 5-minute Apgar (SMD=0.16, 95% CI=-0.06 to 0.39, P=0.15, I²=0%), birth weight (SMD=-0.18, 95% CI=-0.43 to 0.06, P=0.13, I²=0%), and gestational age (SMD=0.13, 95% CI=-0.11 to 0.37, P=0.28, I²=0%). Conclusion: Probiotic or synbiotic supplements are not associated with significant effects on pregnancy outcomes in GDM. However, due to the limited number of studies in this regard and heterogeneity between studies, future high-quality RCTs are recommended.