The placenta is temporary organ which is developed during pregnancy and lasts until the end of pregnancy. It is made of two tissues, maternal (decidua basalis) and fetal (chorion tufting). The presence of the placenta allows the establishment of intimate contact between mother and fetus. The development of the placenta begins with fertilization of the egg, and her function stops by cutting the umbilical cord after the child is born. The placenta in humans is hemo-chorionic-endothelial-type, which means that the endothelium of fetal capillaries in the chorionic villi is in indirect contact with the maternal blood through the trophoblast covering the chorionic villi. During its existence placenta plays multiple roles. The purpose of the placenta is to ensure optimal conditions for the development of the fetus. The functions of the placenta are: nutritional, hormonal, respiratory and excretional function, immunological, protective and hemostatic function. Through the above mentioned functions, the placenta replaces the function of the lungs, kidneys and liver during the development of the fetus.