Definition
The umbilical vein is a blood vessel present during fetal development. Think of it as a lifeline connecting the fetus to the mother. It carries oxygenated, nutrient-rich blood from the placenta to the fetus. After birth, the umbilical vein closes and becomes the ligamentum teres hepatis in the liver. This vein is essential for fetal survival. Unlike most veins, it carries oxygenated blood.