Probiotic Supplements Show Promise for Managing Gestational Diabetes

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Probiotic supplements can help improve blood sugar control among women with gestational diabetes mellitus (GDM). Specifically, probiotics exhibited meaningful benefits for improving insulin resistance and beta cell function — which is important for insulin production — and reducing fasting insulin levels. However, the effect on fasting blood sugar (FBS) was not considered clinically significant.

GMD, which affects between 5% and 20% of pregnant women, is caused by a variety of genetic and environmental influences, such as a history of diabetes, multiple pregnancies, maternal age and obesity. The condition is associated with unfavorable outcomes including miscarriage, preeclampsia and an increased risk of developing type 2 diabetes post birth. It can also lead to excessive birth weight and increase the risk of respiratory problems and birth defects.

To minimize these risks, mothers are encouraged to stay active and eat a healthy diet and may be prescribed pharmacological treatments including insulin, metformin and sulfonylureas. Although the medications can be effective, they can also lead to birth-related complications, large-for-gestational-age infants and neonatal hypoglycemia, and pregnant women can experience dizziness, abdominal issues, diarrhea and hypoglycemia.

“Given the limitations of lifestyle changes and pharmaceutical treatments in managing GDM effectively, it is essential to explore alternative approaches to improve insulin resistance and hyperglycemia,” wrote a team of investigators from the Department of Gynecology and Obstetrics at Shanxi Provincial Children’s Hospital in Shanxi, China. “Despite the growing body of evidence, the results of randomized clinical trials (RCTs) on the efficacy of probiotics in managing GDM have been inconsistent, with remarkable differences in treatment duration, probiotic strains used, dose of treatment, and participant characteristics.”

Investigators conducted a database search of PubMed and Scopus to determine the effects of probiotics on various blood sugar and insulin-related measures in GDM. Eligible studies were published in English from inception to July 2024. Relevant studies were those that assessed pregnant women with GDM who received probiotics alone or in combination with prebiotics and included a comparator (placebo) group.

The study ultimately identified 27 meta-analyses, involving over 33,000 participants. According to the quality assessment, 16 of the studies were deemed moderate quality and 11 were rated as high quality. Any publication bias had minimal impact on the results.

Probiotics were shown to significantly reduce fasting blood insulin (FBI), insulin resistance (HOMA-IR) and beta cell function (HOMA-B). The supplements also improved insulin sensitivity (QUICKI), particularly when taken for seven weeks or less. FBS was also reduced, although investigators did not deem results clinically important.

However, probiotics did not significantly affect HbA1c (long-term blood sugar control), C-peptide (a marker of insulin production) or glucose tolerance tests (OGTT). There was some variability in the data and evidence of publication bias, but no dose-dependent effect of probiotics was found.

Investigators mentioned the high number of studies with moderate to high quality as a strength of the study, as it increased the reliability of results. However, the heterogeneity of the studies reduced the generalizability of the findings. Other limitations included the scarce amount of information on the impact of different probiotic strains and inadequate information on the timing of the interventions. Lastly, as no dose-specific effects were observed, investigators were unable to ascertain the optimal dosage of probiotics for improving glycemic parameters in this patient population.

“This analysis indicated that probiotics could offer beneficial effects on the indices of glucose metabolism in patients with GDM,” investigators concluded. “Yet, to generalize these findings effectively, more clinical trials with larger sample sizes are essential, given the heterogeneity observed across current studies.”