Controlled ovarian stimulation using a long gonadotropin-releasing hormone antagonist protocol: A proof of concept and feasibility study

Background/Aims: To evaluate the feasibility of a long protocol of controlled ovarian stimulation prior to in vitro fertilization (IVF) and embryo transfer with a gonadotropin-releasing hormone (GnRH) antagonist used for pituitary and ovarian suppression. Methods: Thirty patients undergoing IVF/intracytoplasmic sperm injection were randomized into two groups. The control group (n = 16) received a standard flexible GnRH antagonist protocol. Ovarian stimulation consisted of 225 IU/day of recombinant follicle-stimulating hormone for 5 days, followed by 225 IU/day of human menopausal gonadotropin until human chorionic gonadotropin (hCG) administration. The study group (n = 14) received 0.25 mg of GnRH antagonist daily for 7 days, thereafter, upon confirmation of pituitary and ovarian suppression, ovarian stimulation was commenced with the same protocol as used in the control group. Hormone and follicle dynamics, as well as laboratory characteristics and cycle outcome, were compared for both groups. Results: Both groups were comparable in baseline characteristics. Pituitary and ovarian suppression were effectively achieved in 12/14 patients in the study group. The duration of ovarian stimulation and gonadotropin consumption were similar in both groups, as was also the number and size of follicles on hCG day. Conclusion: The results of our study confirm the feasibility of a long GnRH antagonist protocol. This regimen could become another option to optimize GnRH antagonist protocols, and should thus be further explored.