Gonadotropin-releasing hormone antagonists are one of the GnRH analogs that were used in assisted reproductive technologies to produce prompt downregulation of pituitary gonadotropin secretion. During conventional antagonist protocol (CAP), exposure to high LH and E 2 occur that have the potential to worse clinical reproductive results. So the downregulation of pituitary secretion for short period during early follicular phase will result in synchrony in follicular developments and this will improve mature oocytes and total embryos numbers. 44 women as normal responders undergoing ICSI-ET cycles were randomized into two groups. The conventional group (CG) (n 30), gonadotropin started from menstrual cycle day 2 or 3 and continue until hCG trigger day, flexible protocol in which GnRH antagonists administered with follicular size (13-14 mm). In the sandwich group (SG) (n 14), a GnRH antagonist was administered for three days in which GnRH antagonists administered with follicular size (13-14 mm). Gonadotropin started from menstrual cycle day 3 and continue until hCG trigger day. Retrieved and MII oocyte mean numbers were significantly higher in SG than in CG ( P = 0.006, and 0.025), respectively. Embryos and frozen embryos mean total numbers were significantly higher in SG than in CG ( P = 0.004). SG patients have a higher pregnancy rate of 9/14 (64.3 %) than CG 12/30 (40.0 %) although not significant ( P =0.057). Early and short GnRH antagonists proved improvements in synchronization of follicular development, retrieved mature oocytes numbers, total embryos, frozen embryos, and pregnancy rates.