Objective: To compare the efficacy of GnRH antagonist vs. GnRH agonist administration for controlled ovarian hyperstimulation (COH) in assisted reproduction.
Design: A prospective, randomized trial.
Setting: Clinical research unit at a tertiary care medical center.
Patient(s): Sixty-five patients with unexplained infertility or mild male subfertility undergoing COH for IUI.
Intervention(s): Twenty-nine women (group A) were randomized to receive 600 microg of busereline acetate per day starting in the midluteal phase of the cycle (long protocol), whereas 36 women (group B) were treated with 0.25 mg/d of the GnRH antagonist Cetrorelix starting from day 6 of the cycle. The starting dose of recombinant FSH was 150 IU in women of both groups. Insemination was performed 34 hours after hCG injection.
Main outcome measure(s): Clinical and successful ongoing pregnancy rate (PR), measurements of serum FSH, LH, E2, and P, number of recruited follicles, duration of stimulation period, and amount of gonadotropins used.
Result(s): Women in group A required significantly more days of treatment (median: 12.0 vs. 9.0) and significantly more total units of recombinant FSH (median 1,800 vs. 1,550) as compared with the corresponding values of the antagonist group (group B). Serum FSH, LH, E2, and P were significantly higher on the antagonist group on days 2 and 6 of stimulation. However, these differences regress until the day of hCG administration.
Conclusion(s): The GnRH antagonists have facilitated short and simple treatment, and are particularly attractive for administration in women undergoing COH, achieving comparable PR with the long protocol regimen.