A Rationale for Timing of Luteal Support Post Gonadotropin-Releasing Hormone Agonist Trigger.

Gonadotropin-releasing hormone (GnRH) antagonist-based ovarian stimulation protocol is gaining popularity. This protocol allows for the use of GnRH agonist as a trigger of final oocyte maturation, instead of the "gold standard" human chorionic gonadotropin (hCG) trigger. GnRH agonist trigger causes quick luteolysis, hence its widespread use in the context of ovarian hyperstimulation syndrome (OHSS) prevention. To secure pregnancy post GnRH agonist trigger, the luteal phase must be supplemented to counteract the luteolysis. Several luteal phase protocols post GnRH agonist trigger have been suggested, most notably based on increasing luteal luteinizing hormone (LH) activity (by adding LH or hCG). The current review aims at delineating a rationale for timing luteal support with a single hCG bolus post GnRH agonist trigger. The review also suggests a set of simple rules that must be followed when designing luteal phase support post GnRH agonist trigger.