ABSTRACT Aims This study aimed to explore the impact of metformin on gonadotropin levels in women with polycystic ovary syndrome (PCOS) based on a meta‐analysis of randomised controlled trials (RCTs). Methods The search process was performed in PubMed, Scopus, Web of Science, ClinicalTrials.gov and Google Scholar. RCTs were eligible for meta‐analysis if they had a parallel or crossover design and reported gonadotropin levels before and after metformin treatment. A random‐effects model and the generic inverse variance method were used for meta‐analysis. Results The meta‐analysis of 51 RCTs, 48 of which included only and 2 included predominantly women with PCOS, showed that metformin treatment did not affect FSH (WMD: −0.22 IU/L, 95% CI: −0.54, 0.11, p = 0.19, I 2 = 84%) or LH (WMD: 0.11 IU/L, 95% CI: −0.38, 0.60, p = 0.66, I 2 = 75%), but it significantly increased the LH/FSH ratio (WMD: 0.24%, 95% CI: 0.06, 0.43, p = 0.01, I 2 = 93%). Additionally, the effect size was sensitive to one study for FSH, LH and LH/FSH ratio following the sensitivity analysis. Conclusion Our meta‐analysis, the largest one conducted to date, indicates that metformin does not significantly affect circulating gonadotropin levels in reproductive‐age women with PCOS.
Krysiak et al. (Fri,) studied this question.