Inside the Womb

Throughout the stage of fetal development, maternal blood supplies the fetus with nutrients and oxygen, and carries away its waste. These substances diffuse between the maternal arteries and veins, and fetal blood through the placental membrane, and they are carried to and from the fetal body by the umbilical vein and artery within the umbilical cord. Consequently, the fetal blood and vascular system must be highly adapted to intrauterine life in special ways. The placenta is formed from both tissue of the mother and the fetus, maternal arteries and veins. However, blood does not flow directly between mother and fetus, but because of the proximity of the tissues comprising the placental membrane, certain substances diffuse readily.