What is different about the circulation of a fetus before birth and after birth

Due to the special needs of fetal growth and the fact that the fetus is not yet breathing air or using its lungs for oxygen exchange, the circulation of a fetus is substantially different from that of a born infant or adult. Fetal circulation has been modified to support the developing fetus inside the womb, making sure it gets oxygen and nutrients while also getting rid of waste.

Here is a description of how fetal circulation functions:

1) Exchange of nutrients and oxygen:

The placenta, which is attached to the mother's uterus by the umbilical cord, is responsible for supplying oxygen and nutrition to the developing fetus. Through the placental barrier, nutrients and oxygen from the mother's bloodstream permeate into the fetal blood.

2) Blood With Lots of Oxygen:

The umbilical vein transports oxygen-rich blood from the placenta to the developing fetus.
The fetal liver receives this oxygenated blood, and some of it is then diverted there to feed the liver.

3) Ductus Venosus:

The majority of the oxygenated blood leaving the liver enters the duct venosus instead of the fetal liver. The inferior vena cava, a sizable vein that travels to the fetal heart, receives this oxygen-rich blood directly from the duct venosus.

4) Right Ventricle and Right Atrium:

Deoxygenated blood returning from the upper body is mixed with the oxygenated blood entering the inferior vena cava. The right atrium receives the mixed blood, which subsequently goes into the right ventricle.

5) The Foramen Ovale:

The septum (wall) dividing the two atria (left and right) of the fetal heart has a small aperture known as the foramen ovale that allows a considerable amount of the oxygenated blood to bypass the fetal lungs (which are not used for breathing).

Blood can move directly from the right atrium to the left atrium through the foramen ovale, skipping the right ventricle and the lungs in the process.

6) Aorta and left ventricle:

Oxygenated blood is pumped into the aorta from the left ventricle after leaving the left atrium. The fetus then receives this oxygen-rich blood from the aorta, which supplies it with the nutrients and oxygen it needs for growth and development.

7) Deoxygenated Blood:

The superior vena cava carries deoxygenated blood from the fetal body back to the right atrium.
A part of this deoxygenated blood is pushed into the pulmonary artery from the right ventricle.

8) Ductus Arteriosus:

There is a connection between the pulmonary artery and the aorta known as the ductus arteriosus that allows blood to continue to bypass the fetal lungs. This enables the aorta to receive the majority of the deoxygenated blood in the pulmonary artery instead of the lungs.

9) Umbilical Arteries

The two umbilical arteries in the umbilical cord transport the fetus's waste products and deoxygenated blood out of the fetal circulation.
This particular fetal circulation pattern serves to ensure that the growing fetus gets the nutrition and oxygen it needs while putting the least amount of strain on the fetal lungs, which do not function until after birth. When a baby first breathes after birth, there are considerable changes in the circulation as the body adjusts to the new oxygen source from the lungs. As the ductus arteriosus and foramen ovale eventually close, blood flow is redirected to the lungs for oxygenation.