Gonadotropin-releasing hormone antagonist in in vitro fertilization superovulation.

The use of gonadotropin-releasing hormone (GnRH) antagonists in in vitro fertilization superovulation remains controversial. The GnRH agonist 'long protocol' has been seen as the gold standard for many years. Comparisons and meta-analyses of the efficacy of GnRH antagonists and agonists have been largely inconclusive, with the dataset being contaminated with outdated reports of poorer efficacy with GnRH antagonists, which have stemmed from studies of their use as a second-line drug in older women and women who were poor responders.