During which prenatal period are the placenta and umbilical chord formed?

The placenta and umbilical chord are formed during the embryonic period, which lasts from conception to week 8 of pregnancy. During this time, the embryo's major organs and systems begin to develop. The placenta is a specialized organ that connects the developing fetus to the mother's uterine wall and provides oxygen, nutrients, and hormones to the fetus while removing waste products. The umbilical cord is a flexible tube that connects the fetus to the placenta and carries blood, oxygen, and nutrients to and from the fetus.