The document summarizes key information about the amnion and amniotic fluid. It describes the layers of the amnion and notes that it lacks blood, nerve, and lymphatic systems. It discusses the origin, circulation, volume, physical features, and composition of amniotic fluid over the course of pregnancy. The fluid's functions are also outlined, including acting as a shock absorber, maintaining temperature, allowing fetal movement and growth, and flushing the birth canal during labor. Abnormalities in amniotic fluid color are associated with various complications.

1. Amnion
INJETY VINEELA,
ASSOCIATE PROFESSOR
MSc Nursing

2. • Fully formed amnion or amniotic membrane is
0.02-0.05mm in thickness.
• The layers are :
• Single layer of cuboidal epithelium
• Basement membranes
• Compact layer of reticular structure
• Fibroblastic layer and
• Spongy layer
The amnion has got neither blood nor nerve
supply nor any lymphatic system.

3. Amniotic Fluid

4. origin
• The precise origin of the liquor amnii is still
not well understood.
• It is probably mixed maternal and fetal origin.
Circulation: the water in the amniotic fluid is
completely changed and replaced every 3 hours.
The presence of lanugo and epithelial cells in
the meconium shows that the fluid is swallowed
by the fetus.

5. Volume
• Amniotic fluid volume is related to gestational
age.
• It measures about 50ml at 12 weeks, 400ml at
20 weeks and 1000ml at 36-38 weeks.
• Thereafter the amount diminishes by 200ml at
43 weeks.

6. Physical features
• The fluid is faintly alkaline with low specific
gravity of 0.010.
• It becomes highly hypotonic to maternal serum at
term pregnancy.
Color: in early pregnancy it is colorless, but near
term it becomes pale straw coloured due to the
presence of exfoliated lanugo and epidermal cells
from the fetal skin.
It may look turbid due to the presence of vernix
caseosa.

8. Composition
• Water(98-99%)
• Solids(1-2%)
• The followings are the solid constituents:
• Organic and inorganic.

9. Organic
• Protein-0.3mg%
• Glucose-20
• Urea-30
• Uric acid-4
• Total lipids-50
• Hormones
• Creatinine-2

10. Inorganic
• The concentration of sodium chloride and
potassium is almost the same as that found in
maternal blood.
• As pregnancy advances there maybe slight fall
in the sodium and chloride concentration
probably due to dilution by hypotonic fetal
urine, where as potassium concentration
remains unaltered.

11. Suspended Particles
• Lanugo, exfoliated squamous epithelial cells,
vernix caseosa, cast of amniotic cells, cells
from respiratory tract, urinary bladder and
vagina.

12. Functions
• During pregnancy
• During labor

13. During Pregnancy
• It acts as a shock absorber-protecting the
fetus from possible extra uterine injuries.
• Maintains even temperature
• The fluid distends the amniotic sac and
thereby, allows the growth and free
movement of the fetus and prevent adhesion
between fetal parts and amniotic sac.
• Water supply to fetus
• Nutritive value is negligible.

14. During Labor
• Helps in cervical dilatation
• Protects placenta and fetus as long as
membranes remain intact.
• Guards from umbilical cord compression
• Flushes birth canal at the end of first stage of
labor.
• This provides aseptic and bactericidal action
protects of the fetus and prevents ascending
infection to uterus.

15. Clinical importance

16. • Study of the amniotic fluid provides useful
information about the fetal well being and also
maturity of the fetus.
• Excess or less volume of liquor amnii is assessed
by amniotic fluid index.
• With ultrasound, the assessment is performed.
• Maternal abdomen is divided into 4 quadrants.
• Taking the umbilicus, symphysis pubis and fundus
as the reference points.
• The largest vertical point is measured, the sum of
4 measurements is AFI IN centimeters.
• Normal AFI 8-18cm.

17. Abnormal color
• Green-meconium stained liquor
• Golden colour-Rh-incompatability, lysis of RBC
• Greenish yellow(saffron)-post maturity
• Dark coloured-accidental hemorrhage
• Dark brown(Tobacco juice)-Intrauterine deaths
presence of old HB