After administration of GnRH analog at 2nd-3rd day of next menstruation or at least for 14 days in women without menstruation, patients with criteria including serum estrogen (E2) level is below 50 pg/ml, endometrial thickness is <5mm, lack of observation of active follicle on transvaginal ultrasonography will be accepted as down regulation, and gonadotropin therapy [recFSH; Puregon (Organon), Gonal F (Serono), u-FSH/HMG; Merional (IBSA), Menogon (Ferring)] will be started at a properly adjusted dose for each patient. Estimated ovarian response will be considered for each case while determining initial dose. While starting SC/I.M. gonadotropin of average dose 225 IU/day, GnRH analog (Leuprolide acetate; Lucrin, Abbott) will be maintained until hCG day by reducing to 0.5 mg/day doze uninterruptedly. When leading follicle will become 18-20 mm or two of follicles will become 17 mm, ovulation will be triggered by administering 10.000 IU urinary hCG (Pregnyl amp; Organon, Turkey).