GnRH antagonists in assisted reproductive techniques: a review on the Italian experience

Current Controlled Ovarian Stimulation (COH) for Assisted Reproductive Techniques (ART) pursues three main objectives: hypophyseal activity suppression, multiple follicle growth stimulation, and ovulation induction. By suppressing hypophyseal activity, it is possible to prevent untimely LH surge and allow the appropriate development of the leading follicle. The classical GnRH agonist long protocol is the most widely used in COH for ART. However, an alternative regimen based on GnRH antagonist has been recently introduced in clinical practice. As competitive antagonists, these drugs display an immediate and quickly reversible effect and they avoid hormonal withdrawal side effects. Moreover, this protocol shows undeniable advantages, including the shorter duration of the treatment, the lower amount of gonadotropin required, the shorter hormonal and ultrasound monitoring of patients, milder physical and emotional stress, and a lower risk of Ovarian Hyperstimulation Syndrome (OHSS). The use of GnRH antagonists was traditionally restricted to selected patients, as "poor responders" and women at high-risk of developing OHSS such as Polycystic Ovary Syndrome (PCOS) and patients who had previously experienced OHSS. These findings could prompt a trend to change from the standard agonist protocol to the antagonist protocol in all categories of patients. This review provides a comprehensive overview of the use of GnRH antagonist protocols applied both to IVF techniques and to IUI procedures in the Italian experience