n. in embryology, refers to an inner cell mass surrounded by a layer of outer cells known as the trophoblast. It is formed 5 to 6 days after fertilization. After completing its journey through the fallopian tube, it implants on the uterine wall and eventually develops into the embryo.
BLASTOCYST: “A woman may or may not report some spotting at around the time that the blastocyst implants on the wall of the uterus.”