Effects of metformin and ethinyl estradiol-cyproterone acetate on clinical, endocrine and metabolic factors in women with polycystic ovary syndrome

Abstract

Background: Polycystic ovary syndrome (PCOS) is a major endocrine abnormality that affects women of reproductive age. Oral contraceptive pills are usually the first choice of treatment for PCOS when fertility is not desired. Metformin, an insulin-sensitizing drug, has been shown to improve such metabolic abnormality. Aim. To compare the effects of a contraceptive pill in combination with metformin on the clinical, endocrine and metabolic parameters in obese and non-obese patients with PCOS.

Methods: Sixty PCOS patients (25 obese, 35 non-obese) were enrolled in this prospective clinical study. PCOS was defined according to the Rotterdam criteria. Patients were randomized to oral treatment with Diane35 (35 microg ethinyl estradiol plus 2 mg cyproterone acetate), metformin or a combination of Diane35/metformin for 3 months. Body mass index (BMI), waist-to-hip ratio (WHR), Ferriman-Gallwey (FG) score, leuteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, fasting insulin and glucose/insulin ratio were measured at baseline and at the end of treatment.

Results: Diane35 resulted in a higher reduction of FG score in both obese and non-obese PCOS patients compared with metformin. Menstrual regularity was restored in all PCOS patients treated with Diane35 compared with only 28% of those receiving metformin. Metformin significantly decreased BMI and WHR in obese patients (p < 0.05). Testosterone levels decreased in all three groups. LH levels and LH/FSH ratio decreased with Diane35 and Diane35/metformin in both obese and non-obese patients. Metformin significantly decreased fasting insulin concentrations (p < 0.05 and p < 0.01) and increased the insulin sensitivity (p < 0.05) in both obese and non-obese PCOS patients, while no significant changes were observed in the Diane35 group. In addition, insulin levels also decreased (p < 0.05) in the Diane35/metformin group.

Conclusions: Our data show that a combination of metformin and contraceptive pill may be more effective in suppressing the hyperandrogenemia of obese and non-obese PCOS patients than metformin alone and may reduce insulin levels more than contraceptive pill alone. Hence, combined treatment may become a more effective therapeutic option for PCOS.