The blood that flows through the fetus is actually more complicated than after the baby is born (normal heart). This is because the mother (the placenta) is doing the work that the baby’s lungs will do after birth. The placenta accepts the blood without oxygen from the fetus through blood vessels that leave the fetus through the umbilical cord (umbilical arteries, there are two of them). When blood goes through the placenta it picks up oxygen. The oxygen rich blood then returns to the fetus via the third vessel in the umbilical cord (umbilical vein). The oxygen rich blood that enters the fetus passes through the fetal liver and enters the right side of the heart. The oxygen rich blood goes through one of the two extra connections in the fetal heart that will close after the baby is born. The hole between the top two heart chambers (right and left atrium) is called a patent foramen ovale (PFO). This hole allows the oxygen rich blood to go from the right atrium to left atrium and then to the left ventricle and out the aorta. As a result the blood with the most oxygen gets to the brain. Blood coming back from the fetus’s body also enters the right atrium, but the fetus is able to send this oxygen poor blood from the right atrium to the right ventricle (the chamber that normally pumps blood to the lungs). Most of the blood that leaves the right ventricle in the fetus bypasses the lungs through the second of the two extra fetal connections known as the ductus arteriosus. The ductus arteriosus sends the oxygen poor blood to the organs in the lower half of the fetal body. This also allows for the oxygen poor blood to leave the fetus through the umbilical arteries and get back to the placenta to pick up oxygen.

1. Presented by
Mr.Kalyan kumar
Msc (N)

2.  Single umbilical vein carry 80% of oxygenated
blood from placenta towards the fetus. while it
moving towards the heart of the fetus one branch will
give blood to the fetal liver. Then the umbilical vein
enter into the inferior Vena cava through ductus
venosus and it empty into right Atrium.

3.  From right Atrium majority of the blood will
move towards left Atrium via foramen ovale
and the remaining blood will move towards the
right ventricle through tricuspid valve.

4.  The blood in the left Atrium will move to a left
ventricle via bicuspid valve.
 During systole the blood in the left ventricle
move towards aorta and it supplies the body
parts of foetus.

5.  The blood in the right ventricle moves towards
Pulmonary artery, but in the fetal state
pulmonary system pressure is higher than the
systemic pressure, so Blood Will moves from
Pulmonary artery to aorta via ductus
arteriosus.

6.  Two umbilical artery carry deoxygenated blood
from various parts of the fetal body towards the
placenta.
 After the birth of the newborn all these
connections will close and ductus venosus
become ligamentum venosum, ductus
arteriosus become ligamentum arteriosum and
foramen ovale become fossa ovalis.

7. Summary
Conclusion