Introduction – In recent years there has been increased use of the GnRH agonist as the final trigger to complete oocyte (egg) maturation in IVF treatment cycles. While the use of the GnRH trigger has proven quite effective in preventing ovarian hyperstimiulation syndrome, it has not been without drawbacks. The traditional method for completing the maturation of oocytes has been through the administration of human chorionic gonadotropin (hCG). In addition to completing the maturation of eggs, hCG also has a favorable effect on the developing uterine lining. When the GnRH agonist trigger shot is used to complete oocyte maturation, the beneficial effect of the uterine lining is lost, and the uterine lining breaks down very early unless aggressive hormonal supplementation is given. A recent study looks at freezing all embryos in high responder patients when a GnRH trigger shot is used.