Content
1.
2.
3.
What is amniocentesis?
Who is a candidate for
amniocentesis?
What can be detected through an
amniocentesis?
4.
Procedure
5.
After procedure
6.
Rapid test
7.
Full karyotype
8.
Result
9.
Complications of amniocentesis
10.
Conclusion
What is amniocentesis?
 A procedure performed usually in the beginning of
pregnancy to detect chromosomal abnormalities in the
foetus.
 Usually done when a women is between 16 to 22 weeks
of pregnancy.
 During this procedure a sample of amniotic fluid is
taken from the amnion sac (amnion) surrounding the
unborn baby and its DNA is examined for genetic
abnormalities.
 The amniotic fluid- has skin cells of the developing
body, as well as his/her waste products like urine. Each
cell from the baby in fluid contains their complete set of
DNA (genetic information). Analyzing these cells helps
the doctors access the foetus health and detects any
potential problems.
 The
entire
amniocentesis
appointment
lasts
approximately 45 minutes –most of which involves a
detailed ultra sound examination.
Who is candidate for
amniocentesis?
 Any pregnant woman who ,at her due date will be 40 years of
age or older.
 Any women whose combitest results are high risk (blood tests
and/ or foetal ultrasound).
 Any women whose ultrasound results indicate a potential foetal
chromosomal abnormally.
 Any woman who has family history or whose partner has a
family history of one or more incidents of chromosomal
anomalies or genetic disorders with a high recurrence risk.
 It is also possible for women under the age of 40, with no history
of genetic disorder to have an amniocentesis; it is a matter of
personal choice.
What can be detected through an
amniocentesis?
 Nearly all chromosome disorder, including Down’s syndrome as
well as sex chromosome abnormalities.
 Several hundred genetic disorders, such as cystic fibrosis and
sickle cell disease. The test is not used to look for all of them,
but if your baby is at increased risk for one or more of these
disorders, in most cases amniocentesis can usually tell you
whether he/she has the disease.
 Neural tube defects such as spina bifida.
 Amniocentesis is the only way to obtain information about
fetal lung maturity. Amniocentesis is occasionally used late in
pregnancy to assess whether the baby’s lungs are mature
enough for the baby to breathe on his own.
PROCEDURE
1. An ultrasound is used as a guide to determine a safe
location for the needle to insert through the abdominal wall
to enter the amniotic sac. So the fluid may be safely
removed.
2. A sample of amniotic fluid is collected through the needle.
The procedure takes about 45 minutes, although the
collection of fluid takes less than five minutes.
3. The amniotic fluid, which contains cells shed by the foetus,
is sent to the laboratory for analysis.
After procedure
 Advised to rest for 24 hours
 No strenuous work or exercise for 72 hours
 No air travel for 72 hours
 Seek urgent medical attention ifo Feeling shivery
o High fever of 38 degree Celsius or above
o Persistent lower back pain and abdominal pain
 After the amniocentesis procedure, the sample of amniotic
fluid (the fluid that surrounds the unborn baby in the womb)
will be taken to a laboratory for testing.
 There are two different type of tests
o a rapid test
o A full karyotype
Rapid Test
 A rapid test looks for abnormalities on specific chromosomes
(the parts of the body’s cells that carry genes). We can get its
reports within24-48 hours. A rapid test can identify a
number of chromosomal conditions that cause physical and
mental abnormalities. These are:
o Down’s syndrome- symptoms are as follows
1.
2.
3.
4.
5.
6.
7.
Flat facial features.
Small head and ears.
Short neck.
Bulging tongue.
Eyes that slant upward.
Atypically shaped ears.
Poor muscle tone.
o Edward’s syndrome-- symptoms are as follows
1. Physical Abnormalities. Such as small and abnormally
shaped head, abnormally small jaw and mouth, overlapping
fingers and underdeveloped fingernails. Scrunched fists. Lowset ears. ...
2. Heart problems.
3. Developmental disorders.
o Patau’s syndrome-- symptoms are as follows
1.
2.
3.
4.
cleft lip and palate.
an abnormally small eye or eyes (microphthalmia)
absence of 1 or both eyes (anophthalmia)
reduced distance between the eyes (hypotelorism)
5. problems with the development of the nasal passages.

The results of a rapid test should be ready after three working days.
This test is almost 100% accurate, but its only tests for the three
conditions listed above.
Full Karyotype
 Each cell in the body contains 23 pairs of chromosomes. A full
karyotype checks all of these.
 The cells in the sample of amniotic fluid are grown for up to 10
days. In a laboratory before being examined under a
microscope to check for:
o The no. Of chromosomes
o The appearance of chromosome
 Results from full karyotype will usually be ready in 2 or 3
weeks. In about 1 in every 100 tests, the results may not be
clear. This could be due to the mother’s blood contaminating
the sample of amniotic fluid, which may have prevented cells
from growing properly.
Down’s syndrome
Edward’s syndrome
Patau’s syndrome
Result
 After amniocentesis, the sample of amniotic fluid is sent to a
lab for analysis.
 Results usually take 10 days to three weeks depending on the
lab
 It takes that long to get result because the cells have to grow
in the lab in order to analyse them.
 In the lab, genetic and chemical test are done.
 For genetic tests, proteins, minerals and other compounds in
the amniotic fluid are analysed.
 Amniocentesis results will either be positive or negative.
Positive Test result
Negative Test result

If the test result is positive
it means the baby has the
disorder that was being
tested for. One should be
aware that there is no cure
for
the
majority
of
chromosomal conditions,
So she needs to consider
her options carefully.

For most women who have
amniocentesis, results of
the procedure will be
negative. That is, there
baby will not have any
disorders that were tested
for.

Options may include :
1. Continuing with her
pregnancy while getting
information and advice
about the condition. So,
she is prepared for
carrying for her baby.
2. Ending her pregnancy.
3. Options for ending her
pregnancy will depend
on how many weeks
pregnant she is when
making the decision.

It is possible to have a
negative
result
from
amniocentesis but the baby
may still be born with the
condition tested for or
another
chromosomal
condition. This is because a
normal test result doesn’t
exclude every chromosomal
disorder.
Complications of amniocentesis:
 It is important to be aware of the possible complications
during or after amniocentesis. These are outlined below:
Miscarriage:
o There is a small risk that amniocentesis can cause a miscarriage
(the loss of the pregnancy). The risk is estimated to be around 1
in 100.
Club foot:
o Amniocentesis may cause club foot in baby. This is when the
baby is born with a deformed ankle and foot. However , the likely
hood of this happening is higher if you have amniocentesis before
week 15 of pregnancy.
Rhesus Disease:
o Rhesus disease is a condition where proteins in a pregnant
woman’s blood attack her baby’s blood cells.
o Rhesus disease is only possible if the mother’s blood is RHnegative and the baby’s blood is RH-positive. If this is the case,
amniocentesis could trigger RH disease if the mother’s blood is
exposed to the baby’s blood during the procedure.
Injury from needle:
o During amniocentesis, the placenta (the organ that links a
mother ‘s blood to the baby’s blood) may be punctured by the
needle. Sometimes this is necessary to access the amniotic fluid.
If this happens, the puncture wound usually heals without any
problems developing .
o Ultrasound (where high frequency sound waves are used to create
images) is now commonly used to guide the needle. This
significantly reduces the risk of injury from the needle.
Infection:
o In very rare cases, an infection may develop if the procedure
introduces bacteria in the amniotic sac (the sac surrounding the
foetus that contains amniotic fluids). This can cause:




A high temperature (fever) of 38-39 degree Celsius or above
Tenderness of abdomen (tummy)
Contractions (when your abdomen tightens then relaxes).
One should seek medical attention if she has any of these
symptoms. The risk of developing a serious infection from
amniocentesis is estimated to be less than 1 in 1000
Conclusion
Amniocentesis is a safe procedure that can provide
helpful information about the health of foetus. It may
be offered to be a woman who is at high risk of having
a baby with a genetic disease. The risk of miscarriage
of amniocentesis is about 0.5% or 1 in 200.
It is the patient’s decision whether the benefits of
procedure out-weigh the risks.
BIBLIOGRAPHY
1. https://www.mayoclinic.org/testsprocedures/amniocentesis/about/pac-20392914
2. https://americanpregnancy.org/prenataltesting/amniocentesis/
3. https://www.google.com/search?q=amniocentesis&rlz=
1C1CHBD_enIN894IN894&hl=enUS&source=lnms&tbm=isch&sa=X&ved=2ahUKEwijqtLCl
L3pAhVqwTgGHYJXCNcQ_AUoAXoECBYQAw&biw=1366
&bih=625
4. https://en.wikipedia.org/wiki/Amniocentesis
5. Ncert biology book of class 12th