Estradiol-to-Testosterone Ratio Is Associated with Response to Metformin Treatment in Women with Clomiphene Citrate-Resistant Polycystic Ovary Syndrome (PCOS)

Background: To investigate intrinsic alterations in ovarian steroidogenesis in women withclomiphene citrate (CC)-resistant polycystic ovary syndrome (PCOS) whoovulated after metformin treatment.Methods: Fifty-six women of reproductive age (18-40 years) diagnosed with CC-resistantPCOS received metformin for 12 weeks. If ovulation was successfullyinduced by CC after metformin treatment, the women were classified asresponders. Circulating levels of follicle-stimulating hormone (FSH),luteinizing hormone (LH), estradiol (E2), testosterone (T), free testosterone(freeT), fasting insulin and sex hormone-binding globulin (SHBG) weredetermined at weeks 0, 4 and 12 of metformin treatment.Results: Thirty-seven women with CC-resistant PCOS finished the treatment course.There were no significant differences in circulating levels of FSH, E2, T,freeT and fasting insulin at weeks 0, 4, and 12 between responders and nonresponders.At week 4, responders showed significantly higher LH levels andhigher LH/FSH ratios than non-responders (p < 0.005 and p < 0.05, respectively).After the 12-week treatment, responders demonstrated higher serumE2/T ratios and lower freeT levels than non-responders (p < 0.05 and p <0.05, respectively).Conclusions: The results suggest that in women with CC-resistant PCOS, elevated E2/T isassociated with a better response to metformin.