This is a pilot open-label, national, multi-centre, Phase IV trial. This trial will be conducted with outpatients. Once subject has met all eligibility criteria, she will be treated with Gonal-f® prefilled pen and will receive on a randomization basis the GnRH agonist or antagonist. The follicle stimulating hormone (FSH) stimulation will start on day 2 of the menstrual cycle with a pre-defined fixed dose of 150 IU per day until follicles are recruited and developed. Dose adjustment will be allowed strictly in case of risk of ovarian hyperstimulation syndrome (OHSS). Ovulation triggering will be performed using a single injection of 250 mcg Ovitrelle®.