Use of GnRHa for Triggering Final Oocyte Maturation during Ovarian Stimulation Cycles
The use of gonadotropin-releasing hormone agonist (GnRHa) for the final induction of oocyte maturation in in vitro fertilization (IVF) cycles has gained momentum recently over the use of human chorionic gonadotropin (hCG) in women at high risk for ovarian hyperstimulation syndrome (OHSS) (1,2). With increased use of GnRH antagonists for pituitary downregulation and prevention of a premature luteinizing hormone (LH) surge, GnRHa triggering has been advocated as a viable alternative to trigger ovulation by displacement of the antagonist from its receptors, and stimulation of gonadotropin production and release by the anterior pituitary (3,4). Because of the shorter duration of the GnRHa-induced LH surge, earlier demise of the corpus luteum has been observed yielding a significant reduction in the risk for OHSS at the peril of adversely altering embryo implantation (5). Occasionally, a suboptimal LH response to GnRHa has been reported to compromise oocyte yield and/or maturation. For these reasons, the effectiveness of GnRHa triggering has been put to scrutiny, and the quest for the most optimal luteal phase support (LPS) for this type of cycle is also far from being resolved. Earlier studies using this triggering approach were not encouraging because of reportedly high pregnancy losses and low pregnancy rates (6,7).