Metformin in High Responder Polycystic Ovary Syndrome (PCOS) Patients Undergoing IVF Cycles

Infertile young non-obese insulin-resistant patients with PCOS who had a background of the first IVF treatment cycle cancelled because of high risk for OHSS will be enrolled and randomized in two treatment arms. In their second IVF attempt, the experimental group will receive metformin (500 mg, 3 times daily) pre-treatment for two weeks and co-administration during gonadotropins ovarian stimulation; the control group will be treated with placebo (2 cps daily) pre-treatment and co-administration by using the same schedule of the experimental group. In all patients, ovarian stimulation will be carried out with a personalized step-down gonadotropin in association with a minidose flare-up GnRH agonist protocol.