GNRH1 and ovarian hyperstimulation syndrome: In addition, experience with eight patients with exaggerated response suggested that it might prevent the clinical manifestation of OHSS.4 A full review of the hormonal events after GnRH agonist trigger followed.5 As more experience was gained with GnRH agonist triggering, it became apparent that conducting a randomized controlled study, comparing hCG and GnRH agonist triggers in high-risk patients, would be unethical.