Patients undergoing IVF will be included in the study. All patients will be counseled regarding their prognosis. Anti-Mullerian Hormone (AMH) will be measured prior to the initiation of IVF and during ovarian stimulation. Patients will be stimulated with a short GnRH-antagonist protocol. All women will have measurements of serum FSH and estradiol (E2) and a pelvic sonogram on the second day of their cycle. Ovarian stimulation will be initiated with of gonadotropins either in the form of a combination of highly purified urinary FSH and LH or with a combination of Rec FSH and Rec LH. The dose of gonadotropins will depend on the levels of estradiol and FSH prior stimulation. All patients will be re-evaluated on day 3 and 5 of the stimulation (measurment of AMH, E2 and pelvic sonogram), and dosage adjustments will be made and the antagonists (Cetrorelix or ganirelix 0.25 mg/day) will be initiated on day 5. Measurment of AMH, E2 and pelvic sonogram to conferm the size of follicles will be continue every second day untill the oocyte retrieval. When at least 2 follicles reach an average diameter of 17 mm, final oocyte maturation will be triggered with 10,000IU of hCG ( Pregnyl, Organon, Greece Inc.). Oocyte retrieval will be performed 34 to 36 hours later. Patients with successful fertilization will have embryo transfer under sonographic guidance on day 3 after retrieval.