GNRH1 and ovarian hyperstimulation syndrome: The major benefit of GnRH agonist trigger over standard hCG trigger is the significant decrease in incidence of Ovarian Hyperstimulation Syndrome (OHSS), as outlined in numerous studies (17, 18), with one meta-analysis finding an odds ratio of 0.15 (95% confidence interval (CI) 0.05 to 0.47) for developing mild, moderate, or severe OHSS (12).