ABSTRACT
Successful implantation, invasion, and placentation are the result of a complex process that entails the coordination of an euploid embryo, the endometrial factor, and the cross talk between the embryo and the endometrium. This synergetic process is only possible during the window of implantation, a short hormone-dependent period of the menstrual cycle, which has been acknowledged since the first Noyes’ report in 1950. This discovery triggered a race for the search of novel molecular markers initially based on the histochemical analysis of endometrial biopsies for molecules such as integrins, cytokines, and growth factors, which have been thoroughly studied but no longer have clinical application. The evolution of new technologies mainly based in nextgeneration sequencing as well as the possibility of using biological fluids, such as the endometrial fluid, as a source of minimally invasive biomarkers constitute a convenient alternative to traditional methods. Currently, transcriptomic approaches coupled to the development of bioinformatic processing of data offer the most accurate results, making a point over previous biomarkers. Nevertheless, the evolution of social models associated with the increase of infertility among couples and technological developments continue to lead the way for the optimization of current receptivity biomarkers, which can be measured in an accurate, non-invasive, painless, and cost-efficient way.
