Fetal circulation

1. FETAL
CIRCULATION
Presented to Nithya Maam
Department of Pediatrics
Assistance Professor
Presention by Jinu Maharjan
BSC III year
Gayathri College of Nursing

2. Introduction
The fetal circulation is the circulatory system of a
fetus.
The term usually encompasses the entire
fetoplacental circulation, which includes the umbilical
cord and the blood vessels within the placenta that
carry fetal blood.

3. Definition
The circulation of oxygenated blood, de-oxygenated
blood, nutritive material etc in the fetus is termed as
fetal circulation.

4. Anatomy and Physiology of Fetal
Circulation
•Umbilical cord
2 umbilical arteries : return not oxygenated
blood, fecal waste, co2 to placenta
 1 umbilical vein : brings oxygenated blood and
nutrients to the fetus.

5. •Three shunts are present in fetal life:
Ductus venosus: connects the umbilical vein
in the IVC
Ductus ateriosus: connects the main PA to
aorta
Foramen ovale: anatomic opening between
the right and left atrium.

7. Course of Fetal Circulation
1. Placenta:
I. Has the lowest vascular resistance in the fetus.
II. Receives the largest amount of combined (Rt + Lt)
ventricular output.

8. 2. Superior Vena Cava :
I. Drains the upper part of the body, including the
brain.
II. Most of SVC blood goes to the right ventricle.

9. 3. Inferior Vena cava :
I. Drains lower part of body and placenta.
II. Part of IVC blood with high O2 goes into LA
via foramen ovale.
III. Remaining IVC blood enter RV and PA.

10. Pathway of Fetal Circulation

12. 1.In the fetal circulation, there’s an
anatomical opening, a hole called the
foramen ovale which is the connection
between Rt atrium and Lt atrium and so when
blood flows from Rt ventricle blood will also
flow from the Rt atrium to Lt atrium.

13. 2.There is another hole called patent ductus
arteriosus.
The patent ductus arteriosus is the
connection between the PA and the aorta and
so in the fetal circulation blood travelling
through the PA can bypass the lungs and goes
straight to the aorta and be then transported
to the rest of the fetal tissue.

14. 3. The patent foramen ovale and patent
ductus arteriosus allows a Rt to Lt shunt
which means blood normally entering the Rt
side of the heart can easily be shunted to the
Lt side of the heart bypassing the lungs.

15. 4. 1 umbilical vein which is oxygened travels
to the fetal liver and becomes the ductus
venosus which then will join with the IVC.
5. There are two umbilical arteriers and
contain deoxygenated blood and their aim is
to go the placenta to re-oxygenated the blood
via the maternal blood.

16. 6. In placenta, it is really important to understand
that fetal and maternal blood do not actually mix.

18. In the placenta, RBC from maternal
circulation will transfer it’s O2 to the RBC in
the fetal circulation and the fetal RBC will
offload or release their CO2 into the maternal
carbondioxide.
And so the umbilical artery is becoming a
reoxygenated by the maternal circulation.

19. ???
Why is mum giving
O2 to the fetus?

20. • Both the maternal and fetal RBC
contain Hb molecule containing
O2
• But in a fetal RBC there are more
Hb molecule and has more
affinity for O2. This why O2 is
usually taken from maternal RBC
to fetal RBC.

21. The umbilical vein which is now oxygenated
will travel back to fetus via the umbilical vein
and it will go to the heart and then it will be
pumped by the fetal heart to feed the fetal
tissues.