Problems related to the implantation of the human egg after in vitro fertilization.

Egg implantation, the process by which the conceptus comes in contact with the maternal vascular bed, occurs as the consequence of well coordinated ovo-endometrial interactions. In this paper the Authors describe the early steps of the implantation process in the rat. Several changes appearing in the rat endometrium are of particular interest because they also appear in the human endometrium around the normal time for implantation.