Metformin administration in patients with polycystic ovary syndrome who receive gonadotropins for in vitro fertilization cycles: 10-year experience in a large infertile population.

The study aim was to evaluate our personal experience regarding the use and the reproductive effect of metformin administration in a large population of infertile patients with polycystic ovary syndrome (PCOS) undergoing gonadotropins ovarian stimulation for in vitro fertilization (IVF). Infertile patients with PCOS undergoing gonadotropins ovarian stimulation with (metformin group, n = 191) or without (control group, n = 187) metformin and IVF were evaluated. Treatment characteristics, patients' data and reproductive outcomes were evaluated. In all cases, metformin with an immediate-release formulation was administered, and in most of cases it was given as pre- and co-treatment (74.9%) and at a dosage of 1700 mg/day (59.7%). Stimulation length and gonadotropins doses were significantly (p < 0.05) higher in metformin group than in control group. The number of dominant follicles on day of ovarian maturation triggering and peak oestradiol levels were significantly (p < 0.05) lower in metformin group than in control group. Cycle cancellation rate under metformin resulted significantly influenced by interaction with body mass index (BMI), age and basal follicle-stimulating hormone (FSH) levels. Notwithstanding, metformin use in infertile PCOS patients who receive gonadotropins for IVF is not standardized, it seems to modulate the ovarian response to stimulation. This effect may benefit or harm on the basis of ovarian reserve and patients' characteristics.