Nafarelin versus leuprolide in ovulation induction for in vitro fertilization: a randomized clinical trial

Gonadotropin-releasing hormone agonists vary in structure and route of administration. We performed this study to compare patient response to intranasal nafarelin acetate versus subcutaneous leuprolide acetate as adjuncts to ovulation induction for in vitro fertilization (IVF). Forty-two patients entering their first cycle of IVF were randomized to receive either nafarelin acetate or leuprolide acetate. Patient characteristics in the two groups did not differ significantly, nor did cycle cancellation rates or outcome. There was no significant difference in patient response as indicated by follicular phase serum levels of estradiol (E2), FSH, or LH, luteal phase E2, and progesterone. Luteal phase progesterone-dependent endometrial protein was significantly lower in those taking nafarelin acetate, though it remained in the normal range. However, those receiving nafarelin acetate required significantly less human menopausal gonadotropin (hMG) and had significantly more embryos frozen for later transfer than those receiving leuprolide acetate. Intranasal nafarelin acetate can be used successfully in ovulation induction regimens that include GnRH agonists. The use of nafarelin acetate may decrease a patient's hMG requirement and increase the number of frozen embryos available for later transfer as compared with leuprolide acetate. Further studies are needed to optimize the dosing regimen.