Evidence that the Main Adverse Effect of Ganirelix on Pregnancy and Implantation Rates is on the Embryo Rather than the Endometrium

Abstract

Background: At least in our in vitro fertilization (IVF) center the use of ganirelix in controlled ovarian hyperstimulation (COH) protocols for IVF-embryo transfer (ET) has consistently been associated with lower pregnancy rates than when cetrorelix was used in gonadotropin releasing hormone (GnRH) antagonist protocols or when the GnRH agonist leuprolide acetate was used. Objectives: The objective of the present study was to evaluate the pregnancy rates following frozen ET according to the use of these three agents. The finding of lower pregnancy rates with ganirelix following frozen ET would suggest an adverse effect on the embryo rather than the endometrium. Materials and Methods: Clinical (viable at 8 weeks) and live delivered pregnancy and implantation rates following frozen ET were compared in two age groups ≤35 and 36-39 according to use of ganirelix, cetrorelix or luteal phase leuprolide acetate. Single embryo transfers were excluded. Results: The clinical pregnancy rate per frozen embryo transfer in women aged ≤39 whose embryos were formed using ganirelix was 30.0% (52/173) vs. 42.5% (289/680) for cetrorelix and leuprolide acetate combined (P=.0038). The respective live delivered pregnancy rates were 24.8% (43/173) vs. 34.5% (235/680) (P=.019). Similarly the implantation rates were lower with ganirelix showing a 13.1% (69/525) level vs. 20.9% (406/1931 (P<.0001). Conclusions: The adverse effect that some IVF centers notice when using ganirelix in the COH protocol vs. cetrorelix or leuprolide acetate following fresh ET seems to be an embryo defect rather than an endometrial abnormality.