Ovarian stimulation in in vitro fertilization with or without the "long" gonadotropin-releasing hormone agonist protocol: effect on cycle duration and outcome

Objective: To study the correlation between stimulation duration of IVF cycles, with and without GnRH agonist (GnRH-a), and cycle outcome. Design: Retrospective analysis of data. Setting: University-affiliated IVF clinic. Patient(s): 998 IVF cycles in which long GnRH-a protocol was used, and 155 cycles with hMG only. Intervention(s): IVF cycles. Main Outcome Measure(s): Cycle outcome in number of oocytes and embryos, and pregnancy rate. Result(s): The mean stimulation duration (+/-SD) was 9.6 +/- 1.7 and 6.7 +/- 1.0 for the GnRH-a and the hMG-only cycles, respectively (P<0.01). In the GnRH-a group, no statistically significant correlation between cycle duration and pregnancy rate was found. Interestingly, the patients treated for 9 days had the highest number of oocytes retrieved and the highest pregnancy rate. Stimulation duration was not affected by age in either protocol. GnRH-a cycles yielded a significantly higher number of oocytes and embryos compared to cycles without GnRH-a. The pregnancy rate was similar in both groups. Conclusion(s): Stimulation duration in the long GnRH-a protocol group was significantly longer than in the hMG-only group. Stimulation duration was not affected by age. No statistically significant correlation was found between stimulation duration and cycle outcome in the long protocol group. (Fertil Steril(R) 2000,74. 166-8. (C) 2000 by American Society for Reproductive Medicine).