Efficacy of low-dose human chorionic gonadotropin (hCG) in a GnRH antagonist protocol

Purpose: To examine the efficacy of low-dose hCG using a GnRH antagonist protocol. Methods: Prospective randomized study was performed at the Kyono Ladies Clinic. One hundred ninety-two women (< 40-years old, < 3 previous cycles) were randomly assigned to GnRH agonist (buserelin) long protocol (LP, n = 66), GnRH antagonist (cetrorelix) with no low-dose hCG protocol (NhCGP, n = 63), or GnRH antagonist with low-dose hCG protocol (hCGP, n = 63). Results: The hCGP was associated with reduced total amounts of FSH, increased oocyte maturation rate, high-quality day 3 embryos rate, and number of frozen embryos. Ovarian hyperstimulation syndrome (OHSS) tended to be lower in the GnRH antagonist protocol. Pregnancy and implantation rates did not differ significantly between study groups. Conclusions: Daily low-dose hCG supplementation in the late follicular phase could improve the outcome in FSH based-GnRH antagonist protocol. This protocol, however, does require further modifications, including determination of the optimal doses for hCG and gonadotropin pretreatment.