this lecture was presented to the December 2016 Midwifery class of the school for Enrolled Nurses and Midwives- The Gambia.

1. FETAL CIRCULATION:
MR. ABDOU PANNEH
(RM,FWACN,DHAF, NT, RN)

3. INTRODUCTION
• The fetus usually develops it own blood
circulation
• At no given time does the fetal and maternal
blood mix except for some pathological reason
• The fetus produces its own white and red blood
cells
• The fetal respiratory and gastro intestinal tract
system are non functional in-utero.
• The placenta is the sole supplier of oxygen and
nutrients through the umbilical vein.

4. TEMPORAL STRUCTURES
• DUCTUS VENOSUS: (from a vein to a vein). This
vessel originates from the umbilical cord to the
inferior vena cava. It carries replenished and
oxygenated blood from the placenta to the fetal
heart.
• FORAMEN OVALE: This is an opening between
the two atria of the fetal heart. It allows
replenished and oxygenated blood to enter the
left atrium thereby bypassing the right ventricle.

5. TEMPORAL STRUCTURES cont’d
• DUCTUS ARTERIOSUS: (from an artery to an artery).
This vessel branches from the pulmonary artery to
the descending arch of the aorta. It carries
unreplenish and deoxygenated blood from the upper
limbs and head, thereby bypassing the pulmonary
circuit.
• HYPOGASTRIC ARTERIES: These are two vessels that
branches from the internal iliac arteries to enter the
umbilical cord where they become known as the
umbilical arteries. They return deoxygenated and
unreplenish blood to the placenta for oxygenation
and replenishment.

7. BARRIERS (LAYERS)
BETWEEN FETUS & MOTHER
• The syncytium
• The langahan’s
• The mesoderm
• The capillary wall

8. PHYSIOLOGY OF FETAL CIRCULATION
• Carbon dioxide and excretory products are given off
into the maternal blood while the nutritional
substances and oxygen are picked up into fetal
circulation/blood. The replenished and oxygenated
blood now returns to the fetus through the umbilical
vein in the umbilical cord. The blood is led directly to
the liver but before reaching the liver, the ductus
venosus shunt it and directs the blood into the
inferior vena cava, which is at the same time
returning deoxygenated blood from the lower
extremities. At this point, there is a mixture of
oxygenated and deoxygenated bloods.

9. CONT’D
Between the two atria, the foramen ovale allows
oxygenated blood from the inferior vena cava to
pass from the right atrium to the left, instead of
down to the right ventricle as in adult. The blood
then passes from the left atrium to the left
ventricle where it is pumped into the aorta. A
major portion goes to supply the head and upper
limbs, while the small portion supplies the lower
part.

10. CONT’D
• The deoxygenated blood from the upper limbs and
head returns to the right atrium via the superior
vena cava and passes down to the right ventricle as
in adult.
• From the right ventricle, the blood instead of going
to the lungs, it is directed by the ductus arteriosus to
empty into the descending arch of the aorta as the
lungs are non functional. Although a little amount og
blood goes to the lungs to maintain their survival.
The descending aorta supplies the lower aspect but a
large portion is diverted to the placenta by the
hypogastric arteries for oxygenation and
replenishment for the cycle to continue.

11. CONT’D
At birth, the cry of the baby enables air to be
inhaled. This fills and expands the lungs. All
temporal structures also get closed.
WHAT TECHNIQUES WOULD YOU
USE TO STIMULATE A BABY TO
CRY????????????????????????

12. ADAPTATION TO EXTRA-UTERINE LIFE
• As breathing commence soon after birth, normal
blood circulation begins resulting in an increase
pressure on the left side of the heart unlike in
utero. This results in the closure of a flap over the
foramen ovale, preventing direct flow of blood
from the right atrium to the left.
• With the establishment of pulmonary respiration
the oxygen concentration in the bloodstream
rises. This cause the ductus arteriosus to constrict
and close.

13. CONT’D
• The cessation of the placental circulation results
in the collapse of the umbilical vein, the ductus
venosus and the hypogastric arteries.
• These immediate changes are functional and
those related to the heart are reversible in certain
circumstances. Later they becomes permanent
and anatomical.

14. CONT’D
• The umbilical vein becomes ligamentum teres,
the ductus venosus the ligamentum venosum
and the ductus arteriosus the ligamentum
arteriosum. The foramen ovale becomes the
fossa ovalis and the hypogastric arteries are
known as the obliterated hypogastric arteries
except for the first few centimeters, which remain
open as the superior vesical arteries.

15. CONTRIBUTIONS
,
CLARIFICATIONS
&
CONSTRUCTIVE
CRITICISMS????