GnRH antagonists in controlled ovarian hyperstimulation protocols in assisted reproductive technique programmes--current concepts.

Gonadotrophin (Gn) preparations eg, human menopausal gonadotrophins, follicle stimulating hormone both urinary and recombinant have been highly successful in achieving controlled ovarian hyperstimulation which has become the standard practice in assisted reproductive technique cycles. The fine programming of cycles requires blocking of endogenous luteinising hormone surge, the final ovulation trigger. GnRH analogues, both agonists and antagonists which were developed by substituting amino acids are highly effective in preventing LH surge. Both agonists and antagonists have been developed generating a fierce debate regarding the superiority of one above another. This article is a brief review of literature and attempts to clarify following issues: (a) Major differences between agonists and antagonists. (b) Brief outline of antagonist protocol. (c) Comparative advantages and disadvantages. (d) Use of antagonists in various categories of patients. (e) Future! Can antagonists replace agonists?