Intranasal nafarelin versus buserelin (short protocol) for controlled ovarian hyperstimulation before in vitro fertilization: a prospective clinical trial.

The aim of this study was to compare the effect of nafarelin acetate with that of buserelin acetate nasal spray, when administered in a 'short' protocol, as an adjunct to human menopausal gonadotropin (hMG) for controlled ovarian hyperstimulation before in vitro fertilization (IVF). Twenty-two IVF subjects were randomly recruited. Each underwent two consecutive treatment cycles; one with buserelin (900 micrograms/day) and another with nafarelin (400 micrograms/day). The treatment protocol included transnasal gonadotropin-releasing hormone (GnRH) analog from the second cycle day and hMG from the fourth day of the cycle. The buserelin and nafarelin cycles did not differ significantly in the following parameters: baseline hormone profile, duration of GnRH analog treatment, mean hMG dose required, peak estradiol levels, number of preovulatory follicles, number of aspirated oocytes, fertilization rate and number of transferred or frozen embryos. No side-effects or cancellations of treatment were recorded. The average dose required was lower for nafarelin and, because this analog was given only twice a day, it was more convenient to administer. These findings suggest that nafarelin is as effective as buserelin (when administered in a "short' protocol) in achieving controlled ovarian hyperstimulation. It even offers advantages over buserelin with respect to the total dose required (which probably reflects its relatively high potency) and the subjects' compliance.