Gonadotropin-releasing hormone agonist trigger: the way to eliminate ovarian hyperstimulation syndrome--a 20-year experience.

Gonadotropin-releasing hormone agonist (GnRHa) trigger instead of human chorionic gonadotropin in the context of ovarian hyperstimulation syndrome (OHSS) prevention has been used for >20 years. In its first decade it did not gain popularity because it cannot work in GnRHa-based ovarian stimulation protocols. The introduction of GnRH antagonists has revolutionized our ability to eliminate OHSS completely because patients at high risk for OHSS can be triggered with GnRHa. This has been documented in randomized prospective studies, in which none of the patients randomized to the agonist trigger arm developed OHSS. In other words, GnRHa proved to be a potent tool that, truly remarkably, never fails. Although there is some debate concerning the clinical outcome of these cycles, data so far indicate that aggressive luteal support can ensure a good outcome. Moreover, the large number of frozen embryos in these cycles results in excellent per-oocyte retrieval pregnancy rates. In summary, GnRHa ovulatory trigger is the ultimate tool for complete OHSS prevention. GnRH antagonist-based ovarian stimulation protocols should be considered in OHSS high-risk patients so GnRHa trigger can be used if needed.