When where and how placenta develop in human female?

The placenta develops in the human female during pregnancy, beginning shortly after fertilization. It forms from the outer layer of the blastocyst, which is the early stage of the embryo, and embeds itself into the uterine lining around six to seven days post-conception. The placenta serves as a vital organ, facilitating nutrient and oxygen exchange between the mother and the developing fetus throughout gestation. Its development continues until around the 12th week of pregnancy, after which it primarily maintains its function until birth.