Umbilical cord these branches joins with the hepatic portal vein (connecting to its left branch), which carries blood into the liver. The second branch (known as the ductus venosus) bypasses the liver and flows into the inferior vena cava, which carries blood towards the heart. The two umbilical arteries branch from the internal iliac arteries and pass on either side of the urinary bladder into the umbilical cord, completing the circuit back to the placenta. In absence of external interventions, the umbilical cord occludes physiologically shortly after birth, explained both by a swelling and collapse of Wharton's jelly in response to a
Umbilical cord prolapse to congenital anomalies or prematurity, however. It is considered an emergency. The first sign of umbilical cord prolapse is usually a sudden decrease in fetal heart rate that is severe and does not immediately resolve. On a fetal heart tracing, this would usually look like moderate to severe variable decelerations. Occasionally, the cord can be seen or felt on vaginal examination, particularly with overt cord prolapse. Risk factors that are associated with umbilical cord prolapse tend to make it difficult for the fetus from appropriately engaging and filling the maternal pelvis or are related to abnormalities of the umbilical cord.