Inclusion Criteria:  First IVF-ET cycle patients  Exclusion Criteria:  Poor ovarian responder  - At least two of the following three features must be present: (i) Advanced maternal age (≥ 40 years) or any other risk factor for Poor ovarian response (POR); (ii) A previous POR (≤ 3 oocytes with a conventional stimulation protocol); (iii) An abnormal ovarian reserve test (i.e. AFC < 5-7 follicles or AMH < 0.5-1.1 ng/mL)