RESUMEN
The use of GnRH antagonists in assisted reproduction techniques (ARTs) has been shown to be effective in blocking the luteinizing hormone (LH), without a repercussion on ovaric response. The present study reports the use of a GnRH antagonist (cetrorelix) 0.25 mg/d s.c. in patients stimulated with recombinant FSH (rFSH) for IVF/ICSI. 44 patients with mean age of 33.3 years were included in this study, four patients were receptors for oocyte donation program and another patients was receptor for frozen embryos. Controlled ovarian stimulation was carried out with rFSH, starting on day 3 of menstrual cycle. The total mean dose used was 3.570 +/- 1.102 UI for each patient. The LH serum concentrations were monitored during ovaric stimulation, in two patients a premature LH surge (> 10 UI/L) was detected. The oocytes were collected 36 hours after hCG administration, the mean preovulatory oestradiol was 4.006 +/- 2.418 pg/mL. The mean total oocytes retrieved was 10.8 +/- 7.4 per patient, the fertilization rate was 58.3, in only three patients fertilization was failed. No difference was observed in oocyte retrieval, fertilization rate, implantation rate between both groups (GnRH antagonists versus GnRH agonists). The embryo transfer was realized on day 3, and only two patients was on blastocyst stage. In 17 of 41 patients with successful transfer, pregnancy was achieved in the group with antagonists, and 8 of 20 patients in the group with agonists. In conclusion Cetrorelix prevents adequately premature LH surges and allows an effective ovaric response in controlled stimulation in IVF cycles, except in patients in oocyte donation programs who require higher cetrorelix doses.