Differential dose of antagonist (Ganirelix) relative to exogenous FSH

Abstract

We read with interest the article by de Jong et al. (1de Jong D. Macklon N.S. Eijkemans M.J.C. Mannaerts B.M.J.L. Coelingh Bennink H.J.T. Fauser B.C.J.M. Dynamics of the development of multiple follicles during ovarian stimulation for in vitro fertilization using recombinant follicle-stimulating hormone (Puregon) and various doses of the gonadotropin-releasing hormone antagonist Ganirelix (Orgalutran/Antagon).The Ganirelix Dose-Finding Study Group. Fertil Steril. 2001; 75: 688-693Abstract Full Text Full Text PDF PubMed Scopus (33) Google Scholar) on the dynamics of the development of multiple follicles during ovarian stimulation for IVF using recombinant FSH (Puregon) and various doses of GnRH antagonist. The authors concluded that follicular growth was not influenced by the daily dose of GnRH antagonist in ovarian hyperstimulation protocols for IVF. This statement may be considered accurate if the dose of recombinant FSH administered in the different groups was the same. This was not the case, however (Table 1 in that paper). With GnRH agonists, the secretion of endogenous gonadotropins is fairly constant during stimulation, whereas endogenous FSH and LH secretion will decrease when antagonist is started (2de Jong D. Macklon N.S. Fauser B.C.J.M. A pilot study involving minimal ovarian stimulation for in vitro fertilization extending the ‘follicle stimulating hormone (FSH) window’ combined with the gonadotropin-releasing hormone antagonist cetrorelix.Fertil Steril. 2000; 73: 1051-1054Abstract Full Text Full Text PDF PubMed Scopus (69) Google Scholar). Serum concentrations of FSH in de Jong et al.’s study reflect the sum of exogenous FSH and endogenous FSH, possibly suppressed by GnRH antagonist. In an attempt to enhance the response detected by ultrasonography, clinicians may increase the dose of recombinant FSH, which we may assume was done in the present study. Could the difference in the dose of recombinant FSH seen in Table 1 explain why follicular growth was not influenced by the changing dose of GnRH antagonist? Differential dose of antagonist (Ganirelix) relative to exogenous FSHFertility and SterilityVol. 76Issue 5Preview Full-Text PDF