Embryo implantation is the least well known phase of reproduction within the field of reproductive medicine. This fact is of special relevance if we also take into account that the human embryo is not very efficient when compared to other closely-related species in the evolution timeline.
We currently know that pregnancy is based upon three basic pillars: the embryo, the endometrium and the tolerance of the mother’s immune system. Not only is it essential that all three function correctly, but there needs to be optimum interaction between them. We have already covered the role of the embryo and the immune system in detail. Therefore, we will now concentrate on the endometrium and, more specifically, on studying endometrial receptivity. […]