The umbilical vein is the single vein within the umbilical cord that carries oxygenated, nutrient-rich blood from the placenta to the fetus. Inside the fetal abdomen, the umbilical vein connects to the ductus venosus, which shunts a portion of the blood directly to the inferior vena cava, bypassing the liver. On ultrasound, the umbilical vein is identified within the cord and can be followed into the fetal abdomen. Doppler assessment of the umbilical vein normally shows a continuous, non-pulsatile flow pattern. Abnormal pulsations in the umbilical vein can indicate fetal heart failure or increased pressure in the fetal venous system, and this finding in the setting of growth restriction is particularly concerning. After birth, the umbilical vein obliterates and becomes the ligamentum teres of the liver.
Sonography Term