Engmann et al. [87] showed that this approach was effective in a clinical study in which 66 patients at high risk for developing OHSS were randomized to an ovarian stimulation protocol consisting of either a GnRH agonist trigger after co-treatment with ganirelix or a control group that received hCG trigger after dual pituitary suppression with birth control pills and a GnRH agonist. Here, GNRH1 is linked to ovarian hyperstimulation syndrome.