Depot GnRH agonist versus the single dose GnRH antagonist regimen (cetrorelix, 3 mg) in patients undergoing assisted reproduction treatment

The objective of this study was to compare, in a centre with previous experience of gonadotrophin-releasing hormone (GnRH) antagonist use, single administration of a GnRH antagonist cetrorelix (Cetrotide) 3 mg] with a single administration of a GnRH agonist Decapeptyl Retard 3.75 mg] in patients undergoing assisted reproduction treatment (n = 307 and 364 respectively). GnRH agonist was administered on the first day of menses, while cetrorelix was administered when the largest follicle reached 14 mm. Ovarian stimulation was performed with recombinant human FSH (r-hFSH; 150-225 IU/day). Human chorionic gonadotrophin (HCG, 10,000 IU) was administered when at least two follicles reached a mean diameter > or =18 mm. Over 90% of patients in both groups reached the criteria for HCG administration and underwent oocyte retrieval and embryo transfer. Duration of FSH therapy (9.95 versus 11.25 days) and cumulative dose of r-hFSH (1604 versus 1980 IU) were significantly reduced (P < 0.01) in the cetrorelix 3 mg group. The number of oocytes retrieved was lower (8.5 versus 11.2; P < 0.01) with cetrorelix, but the number of embryos replaced was similar (2.2 versus 2.3; NS). The pregnancy rates per oocyte retrieval were the same, 24.5%, in the antagonist and agonist groups. This study indicates that although fewer oocytes are recovered, similar pregnancy rates can be achieved with a GnRH antagonist compared with a GnRH agonist. Additionally, a single dose of 3 mg cetrorelix was administered in 84% of patients, thus being simpler and more convenient for patients. Cetrorelix 3 mg may thus be proposed as a first choice for preventing both a premature LH surge and detrimental rises in LH during ovarian stimulation prior to assisted reproduction treatment.