005. PREPARING FERTILE SOIL: THE IMPORTANCE OF ENDOMETRIAL RECEPTIVITY

Abstract

The human endometrium is receptive for implantation of a blastocyst, for only 4–5 days in each menstrual cycle. Failure of implantation is a major reason for infertility in women, and the inability to achieve endometrial receptivity is responsible for much of the failure of reproductive technologies. Endometrial receptivity requires alterations in the uterine luminal and glandular cells, particularly in terms of their secretory capacity and altered expression of adhesion molecules, along with decidualization of the endometrial stroma, which in women is initiated during the receptive phase, regardless of the presence of a blastocyst. Increased leukocyte numbers are also important. The microenvironments provided by the endometrium during the receptive phase and which support implantation are highly complex and constantly changing. The present review summarizes work from our laboratories and others, regarding these microenvironments, how they impact on receptivity and how they are disturbed in infertile women. Such microenvironments can also be manipulated to provide new contraceptive strategies for women.