GNRH1 and ovarian hyperstimulation syndrome: An RCT including 302 patients with normal gonadotropin levels divided into two groups, hCG trigger or GnRH-a trigger with a bolus of 1.500 IU hCG after 35 hours ,there was not a significant difference in birth rates between two groups (24% vs. 31%, respectively) and the incidence of OHSS rate (moderate and severe), was 2% after hCG trigger and no OHSS case in GnRH-a trigger was reported (7).