GNRH1 and ovarian hyperstimulation syndrome: A large RCT including 1050 first IVF cycles recently demonstrated that the incidence of severe OHSS (5.1% vs. 8.9%; p=0.02) and moderate OHSS (10.2% vs. 15.6%; p=0.01) was significantly lower in the GnRH antagonist group compared with the agonist group, respectively, and pregnancy rates were similar in the two groups (40).