Detailed explanation of the implantation process of the fertilized egg

This template comprehensively explains the biological process of implantation, from the development of the zygote (zygote) to the blastocyst stage, through zona pellucida shedding, contact with the endometrium, adhesion, and ultimately, implantation. It details the regulation of the implantation window, hormonal signaling (e.g., progesterone and estrogen), changes in endometrial receptivity (e.g., epithelial cell surface molecule expression), and embryo-maternal communication (e.g., cytokine and integrin-mediated interactions). It also highlights common factors for implantation failure (e.g., embryo quality, endometrial abnormalities) and their clinical relevance (e.g., optimization of assisted reproductive technology). This template is suitable for reproductive medicine education, embryology research, infertility treatment, and public health awareness, with scientifically rigorous content that adheres to physiological standards.