Cycle cancellation was defined as three groups : [1] poor ovarian response : fewer than two growing follicles on transvaginal ultrasound, and an E₂ level < 200 pg/ml on the day 7 of stimulation ; [2] failed oocyte retrieval : no obtained oocyte on the day of ovarian puncture ; [3] failed fertilization : no fertilized oocyte after IVF/ICSI.