Triggering final follicular maturation for IVF cycles.

As part of a conventional controlled ovarian hyperstimulation (COH) regimen, final follicular maturation is usually triggered by a single bolus dose of human chorionic gonadotropin (hCG). COH, which combines GnRH antagonist co-treatment with GnRH agonist(GnRHa) trigger, is often used in attempts to eliminate severe early ovarian hyperstimulation syndrome and to improve oocyte/embryo yield and quality. Recently, the combination of GnRHa, with hCG trigger has also been implemented into clinical practice. Here, we analyze and discuss published studies on various ways of triggering final follicular maturation, seeking to elucidate the appropriateness of each approach for specific patient subgroups.