GNRH1 and ovarian hyperstimulation syndrome: GnRH antagonist rescue protocol (replacing GnRH agonist with GnRH antagonist and reducing the dose of gonadotropins to 75 IU/day) combined with cabergoline is more effective than cabergoline alone in the prevention of OHSS in patients downregulated with GnRH agonist who are at high risk for OHSS.