A comprehensive search was carried out among the English-language databases, including PubMed, Scopus, Cochrane Library, Google Scholar, and Web of Science, and the articles published from April 2010 to February 2019 were tracked down. The fixed and random-effects meta-analysis was used to estimate the pooled effect size. The meta-analysis was performed in Stata Version 14.0.
Nine studies with 331 patients treated with metformin and 307 patients treated with myo-inositol groups were included in the analysis. The research groups did not diverge significantly in terms of the basic characteristics, such as age and Body Mass Index (BMI). In the myo-inositol group, the levels of Luteinizing Hormone (LH) [12.55% (95% I: 11.41-13.68%)], S. testosterone [44.38% (95% CI: 38.09-50.67%)] and prolactin [7.97% (95% CI: 6.58- 9.37%)] were significantly higher than those recorded, i.e., LH [7.97% (95% CI: 6.58- 9.37%)], S. testosterone [8.48% (95% CI: 3.14-13.83%)] and prolactin [7.14% (95% CI: 1.50-14.79%)] for the metformin group (p<0.001).
Due to the dearth of related research and the high heterogeneity of the Randomized Clinical Trials (RCTs) included in other studies, the present systematic review could not establish any differences between metformin and myo-inositol concerning the hormonal profile and the ovarian function. However, the findings indicated that myo-inositol could improve fertility outcomes by modulating hyperandrogenism. Randomized trials are required to understand the mechanistic actions of myo-inositol in comparison with those of metformin regarding oocyte and embryo quality, fertilization, pregnancy, and live birth rates.