Implantation and placenta formation

This session centers on implantation and placenta formation, offering a structured look at the processes of embryonic implantation and placental development, beginning with blastocyst formation and the stages of implantation into the endometrium. We will discuss the differentiation of trophoblast cells, the establishment of maternal fetal circulation, and the critical roles of the placenta in nutrient exchange and immune protection. Finally, we will highlight the importance of hormonal regulation in maintaining pregnancy and supporting fetal growth. Embryonic implantation and placental development are crucial events in establishing and maintaining pregnancy. After fertilization, the zygote divides as it travels down the fallopian tube, forming a blastocyst by the fifth or sixth day. The blastocyst contains an inner cell mass, which will become the fetus and an outer trophoblast layer. Implantation involves apposition, stable adhesion, and invasion stages, or requiring coordinated cellular and molecular interaction for successful embryo implantation and placental formation. Implantation begins with the blastocyst hatching from the zona pellucida, exposing the trophectoderm. Upon contacting the receptive endometrium, the trophectoderm differentiates into two trophoblast populations, the cytotrophoblast forming an inner layer and the sensetiotropho blast, a multinucleated outer layer that invades the endometrial stroma. This invasion anchors the embryo and