In patients with PCOS, there were no significant differences between the GnRH antagonist and PPOS groups in regards to gonadotropin dose, E2 on hCG trigger day, and numbers of oocytes retrieved, MII, 2PN and blastocysts, whereas the stimulation time (10.05 ± 1.75 vs. 9.58 ± 1.38; P=0.022) and oocyte yield (95.0% vs. 91.1%; P<0.001) were higher in the GnRH antagonist group than in the PPOS group, with results similar to those of NOR (Table 2). Here, GNRH1 is linked to polycystic ovary syndrome.