In fetal development the IVC is the continuation of which vessel?

• A. Umbilical vein
• B. Ductus venosus
• C. Portal vein
• D. Renal vein

Answer: (B)

In fetal circulation, blood from the placenta reaches the fetus through the umbilical vein and is directed into the heart mainly via the ductus venosus, which shunts this oxygen-rich blood directly into the inferior vena cava while bypassing the liver. Because the ductus venosus feeds straight into the IVC, the inferior vena cava is essentially the continuation of the ductus venosus. After birth, the ductus venosus closes and becomes the ligamentum venosum. The other vessels don’t fit this role: the umbilical vein brings blood to the ductus venosus, the portal vein handles hepatic portal flow to the liver, and the renal veins drain the kidneys into the IVC rather than forming its continuation.