The present prospective study was designed to compare the effects of administering a daily dose of gonadotrophin releasing hormone (GnRH) antagonist vs. an alternate-day dosage of GnRH agonist on ovarian response and in vitro fertilization (IVF) outcome in patients stimulated with recombinant follicle-stimulating hormone (FSH) and human chorionic gonadotrophin (hCG) microdose.