Gonadotropin-releasing hormone agonist versus human chorionic gonadotropin for triggering follicular maturation in in vitro fertilization

Abstract

To compare the use of gonadotropin-releasing hormone agonist (GnRH-a) with human chorionic gonadotropin (hCG) for triggering the final stage of follicular maturation for in vitro fertilization (IVF). In vitro fertilization outcome was determined in a randomized, prospective study. The University of Toronto IVF program at The Toronto Hospital, Toronto General Division. One hundred seventy-nine women in the IVF program were given a subcutaneous injection of leuprolide acetate (500 μ g) or an intramuscular injection of hCG (5,000 IU) 34 to 36 hours before oocyte retrieval. Vaginal progesterone (P) suppositories (50 mg) were used two times a day for luteal phase support. A subgroup of 41 women had serum estradiol (E 2 ) and P levels determined 2 and 7 days after embryo transfer (ET). Pregnancy rates and luteal phase E 2 and P were compared. In the GnRH-a group, there were 18 pregnancies from 84 ETs (20%). In the hCG group, there were 19 pregnancies from 95 ETs (19%). Luteal phase E 2 and P levels were significantly lower in the GnRH-a group compared with the hCG group, and 18% of the former group had an apparent short luteal phase. Gonadotropin-releasing hormone agonist appears to be an effective alternative to hCG for inducing follicular maturation in IVF. The lower luteal phase E 2 concentrations may potentially be beneficial in preventing ovarian hyperstimulation and for enhancing implantation. Better luteal phase support or a different dose of GnRH-a is needed to prevent luteal phase deficiency.