Superior vena cava
Inferior vena cava
Hepatic portal vein
Common iliac artery
Medial umbilical ligaments
Very low oxygenation
Circulation in fetus and
Arrows on blood vessels indicate
direction of blood ﬂow. Arrows in color
screens go from the fetal structure to what it
becomes after birth.
for embryonic and fetal life. The umbilical
vein carries oxygen- and nutrient-rich blood
from the placenta to the fetus. The umbilical
arteries carry waste-laden blood from the
fetus to the placenta. The ductus arteriosus
and foramen ovale bypass the nonfunctional
lungs. Note that blood passing through the
foramen ovale comes mostly from the inferior
vena cava. The ductus venosus allows blood
to partially bypass the liver.
in the cardiovascular system at birth. The
umbilical vessels as well as the liver and lung
bypasses are occluded.