Abstract
The introduction of the gonadotrophin-releasing hormone (GnRH) antagonists offers new potential for in vitro fertilization (IVF) clinics. Compared with GnRH agonists, the use of the GnRH antagonists significantly reduces the dose of gonadotrophin and duration of treatment required, and also reduces unwanted side-effects. Patients also tend to prefer treatment with GnRH antagonists compared with agonists. The GnRH antagonists are useful in both good and poor responders, and there is some flexibility in treatment protocols. A single dose of GnRH antagonist may be used in patients who do not want or require more aggressive stimulation. Promising data indicate advantages of GnRH antagonists in terms of reduced incidence of ovarian hyperstimulation syndrome and reduced impairment of luteal function. It is anticipated that, as a result of further development of treatment protocols, pregnancy rates with the GnRH antagonists will become at least equivalent to those achieved with GnRH agonist protocols.