Gonadotrophine Releasing Hormone Agonist As A Trigger of Ovulation in poly cystic ovary syndrome

Abstract

Gonadotropin-releasing hormone agonist (GnRH-a) has been used to suppress gonadotropins in several conditions including endometriosis, uterine fibroids, central gonadotropin-dependent precocious puberty, where gonadotropin suppression does not occur immediately, but there is a transient increase "flare" in sex hormone levels, followed by a lasting suppression of hormone synthesis and secretion. When using GnRH analogues to trigger ovulation, the mean concentration of LH as measured by radioimmunoassay may be actually raised although there is reduced pulsatile secretion and so the bioactive LH is markedly reduced, where the GnRH-a induced surge consists of two phases; a short ascending one (4h) and a long descending one (20 h), with subsequent induction of an FSH surge comparable with the surge of the natural cycle.