Embryonic implantation

Embryo implantation is a progressive process which requires a communication between two different organisms, and consists of three consecutive phases: apposition, adhesion and invasion. It must be realized throughout the peri od called << window of implantation>>, which is characterized by morphologi cal and biochemical changes in the endometrium, as the plasma membrane tran sformation and the presence of some specific adhesion molecules, chemokines , cytokines, growth factors, and invasive proteinases. All of then acting i n a paracrine/autocrine manner, and drive by endocrine hormones.