What are the 3 fetal shunts?
Three shunts in the fetal circulation
- Ductus arteriosus. � protects lungs against circulatory overload. � allows the right ventricle to strengthen.
- Ductus venosus. � fetal blood vessel connecting the umbilical vein to the IVC.
- Foramen ovale. � shunts highly oxygenated blood from right atrium to left atrium.
What are the three fetal shunts and why do they exist?
The fetal circulatory system uses three shunts, which are small passages that direct blood that needs to be oxygenated. The purpose of these shunts is to bypass certain body parts–in particular, the lungs and liver–that are not fully developed while the fetus is still in the womb.
What is the Venus duct?
The ductus venosus is a shunt that allows oxygenated blood in the umbilical vein to bypass the liver and is essential for normal fetal circulation.  Blood becomes oxygenated in the placenta and travels to the right atrium via umbilical veins through the ductus venosus, then to the inferior vena cava.
What happens to ductus venosus?
The ductus venosus naturally closes during the first week of life in most full-term neonates; however, it may take much longer to close in pre-term neonates. Functional closure occurs within minutes of birth. Structural closure in term babies occurs within 3 to 7 days.
What happens to ductus venosus after birth?
Postnatal closure The ductus venosus naturally closes during the first week of life in most full-term neonates; however, it may take much longer to close in pre-term neonates. Functional closure occurs within minutes of birth. Structural closure in term babies occurs within 3 to 7 days.
Which shunt closes first after birth?
The ductus venosus closes during the first week of infancy and becomes the ligamentum venosum. When, in the new-born, the blood returns to the left atrium the foramen ovale closes somewhat like a door from left to right.
Why do shunts close after birth?
With the first breaths of life, the lungs start to expand. As the lungs expand, the alveoli in the lungs are cleared of fluid. An increase in the baby’s blood pressure and a major reduction in the pulmonary pressures reduce the need for the ductus arteriosus to shunt blood. These changes help the shunt close.