ABSTRACT
During the past decade, assisted reproductive technologies (ART) have undergone considerable clinical and laboratory advances. Although success rates have generally risen over the years, most women undergoing a cycle of ART fail to become pregnant. Typically, embryo implantation rates remain below 15% even when super-numerary embryos are transferred. Although multiple gestations are a common problem, approximately 70 to 90% of viable embryos fail to implant (Amso and Shaw, 1993). Undoubtedly, successful implantation of transferred embryos involves numerous factors, most of which remain undefined. However, if success rates in ART are to improve, a better understanding of early implantation is required.
