ABSTRACT
Implantation of a mammalian blastocyst into the endometrium is a complex process and requires a series of precisely synchronized physiological and cell biological events. Disruption of this synchrony in the differentiation process of the blastocyst and the uterine
epithelium leads to failure of implantation. Although reproduction is critical to species survival, establishment of pregnancy is inefficient in humans. Here, 20% of spontaneous abortions during pregnancy are estimated to occur before pregnancy is detected clinically,1 and the pregnancy rate in in-vitro fertilization (IVF) programs still remains as low as 20-30% in spite of the high rate of
successful fertilization.2 Although this inefficiency of the implantation process could in part be considered as a gatekeeper to support only healthy embryos for ongoing pregnancies, the molecular mechanisms of this impairment in the feto-maternal cross-talk need clarification.
