The umbilical cord, surrounded by the amnion, contains two umbilical aeries, one umbilical vein and Whaon&;s jelly, which serves as a protective cushion for the vessels. Single Umbilical aery is associated with other congenital anomalies and observation of a two-vessel cord with a single umbilical aery in a new born should prompt one to look carefully for additional anomalies. Umbilical aeries: The umbilical aeries are paired branches of the internal iliac aeries. These pass through the connective stalk (umbilical cord) and become continuous with the chorionic vessels of the developing placenta. These vessels carry deoxygenated blood. Fate(after bih) : The proximal poion of the umbilical aery persist as the internal iliac and superior vesical aeries. The distal pas are obliterated to form the median umbilical ligaments. Single umbilical aery: (Seen in 1 to 2% of pregnancies) It is associated with aneuploidy as well as renal and cardiac abnormalities Observation of a Single Umbilical aery (two-vessel cord) should prompt one to loom carefully for additional anomalies in a newborn. Umbilical Veins: Umbilical veins appear as a pair of vessels to return blood from placenta to the fetus. The right umbilical vein is obliterated during the fifth gestational week. Left vein is left (right is obliterated) These vessels carry oxygenated blood. The oxygenated blood is shunted through the ductus venosus into the inferior vena cava and the hea. Fate (After bih) : The left umbilical vein obliterates to form ligamentum teres. Ref: Nelson 20th edition Pgno: 890