The effects of probiotics supplementation on metabolic health in pregnant women: An evidence based meta-analysis

Evidence-based meta-analysis of probiotic supplementation studies in pregnant women, including healthy pregnancies, women with overweight or obesity, and women with gestational diabetes mellitus. Outcomes focused on maternal metabolic markers such as fasting glucose, insulin, insulin resistance indices, and lipids.

Pregnant participants received oral probiotic supplements containing various Lactobacillus and Bifidobacterium strains, including L. rhamnosus GG with B. lactis Bb12, L. acidophilus with B. animalis Bb12, multi-strain capsules, L. salivarius UCC118, and VSL#3. Doses ranged from 10^7 cfu to >4 × 10^9 cfu, given from early pregnancy or the third trimester through 6 to 12 weeks, until delivery, or until the end of exclusive breastfeeding; comparators included placebo, diet, or usual care.

Overall, probiotics during pregnancy were associated with better glucose metabolism, with several trials reporting lower fasting glucose, insulin, HOMA-IR, or improved QUICKI in healthy and GDM pregnancies. Notable study-level findings included reduced plasma glucose and improved insulin sensitivity in one healthy-pregnancy trial (P = 0.025 and P = 0.028), reduced GDM frequency in another healthy-pregnancy trial (P = 0.03), and improvements in fasting glucose, insulin resistance, and related markers in multiple GDM trials. Lipid effects were inconsistent: some GDM studies reported lower total cholesterol, LDL cholesterol, triglycerides, or VLDL, but other trials found no clear lipid change. In obese pregnant women, no clear metabolic benefit was observed, and the authors concluded that larger high-quality trials are still needed to define optimal strains, dosing, and long-term maternal and offspring effects.

The evidence base was small and heterogeneous, with different probiotic strains, doses, start times, and treatment durations across studies. Per-arm sample sizes were often not reported, several outcomes were supported by only a few trials, and data in obese pregnant women were sparse. Long-term maternal and offspring outcomes were not well characterized.