Fetal Circulation

fetal and newborn circulation

I actually wanted to write about congenital heart disease. However, to understand congenital heart disease, we should first understand the difference between fetal and newborn circulation. In this post, I will explain how fetal circulation works.

The oxygenated blood from placenta is carried by vena umbilicalis to the liver. Some blood is bypassed to ductus venosus. After that, the blood is carried to vena cava inferior.

From vena cava inferior, the blood goes to atrium dextrum (right atrium). One third of the blood pass through foramen ovale to atrium sinistrum (left atrium), then to ventriculus sinistrum (left ventricle). It is then circulated to heart, brain, and upper extremities.

What about the two third of the blood? Two third of the blood is mixed with vein blood from upper body. It then enters ventriculus dexter (right ventricle) and is pumped to arteri pulmonalis. Most of the blood passes ductus arteriosus and goes to aorta descendens. A little of the heart enters pulmonary circuit.

How does the circulation adapt when the baby is born? I will write about that in the future.


  1. If you find that I make mistake in this post, either the mistake in anatomical term, the pathway, or anything, please tell me.
  2. If you’re confused or want to ask something about fetal circulation, just ask.
  3. If the picture can’t be seen clearly, please let me know.


Kliegman, Robert M in Behrman, Richard E. 2010. Esensi Pediatri Nelson ed. 4. Jakarta: EGC.

Marieb, E. and Hoehn, K. (2013). Human anatomy & physiology. Boston: Pearson.

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