Effect of probiotics combined with metformin on improvement of menstrual and metabolic patterns in women with polycystic ovary syndrome: a randomized clinical trial

Objectives: The aim of this study was to access the efficacy of probiotics combined with metformin on improvement of menstrual and metabolic patterns in women with polycystic ovary syndrome (PCOS). Methods: In this single-centre, controlled, randomized clinical trial (NCT03336840), 60 non-obese women with PCOS were randomly assigned (1:1:1) to receive probiotics (4 g daily), metformin (1.5 g daily) or their combination for 12 weeks. The primary outcome was the improvement of menstrual patterns. The secondary outcomes included changes in anthropometric, metabolic profiles and hormonal levels. Results: After 12-week treatment, the recovery rate of menstrual cycle was 40% in probiotics group, 55% in metformin group and 80% in combination group (p = 0.035). Meanwhile, the ovulation rate was 30% in probiotics group, 55% in metformin group and 75% in combination group (p = 0.017). Serum anti-Müllerian hormone, testosterone, free androgen index, BMI, fasting blood glucose, HOMA-IR, lipid profiles were decreased after probiotics or metformin treatment in non-obese women with PCOS. Conclusion: In the present trial, probiotics combined with metformin was superior to probiotics or metformin alone to improve menstrual patterns in women with PCOS. Metabolic and hormonal profiles were also improved after probiotics or metformin treatment.