What
is it?
This is a test in which a small amount of fluid
which surrounds the baby in the womb is taken
off and sent to the laboratory for genetic analysis.
It can be performed as early as 14 weeks onwards. |
Why Is The Test Done?
This test is advisable for those who are over
35 years of age, in view of the increased risk of the
baby having a chromosomal abnormality such as Down’s
Syndrome. Women with a family history and abnormal blood
tests results are also at higher risk.
The
Chance Of Having A Down’s Syndrome Baby |
25 |
1 in 1,500 |
|
38 |
1 in 170 |
30 |
1 in 800 |
|
39 |
1 in 140 |
35 |
1 in 350 |
|
40 |
1 in 100 |
36 |
1 in 300 |
|
45 |
1 in 25 |
37 |
1 in 200 |
|
|
|
What Will The Test Show?
The fluid is tested for chromosomal disorders, of
which Down’s Syndrome is the most important.
If there is a family history of certain inherited
diseases it may be possible to test for these also.
Amniocentesis will not necessarily exclude subtle
chromosomal abnormalities or mosaicism.
How Is It Done?
The test takes place in the Ultrasound room. You will have the opportunity
to ask questions or discuss any problem with the
staff. One relative may stay with you during the
procedure if you wish.
You will have a short ultrasound scan before and
after the test. No anesthetic is required and meals
may be taken as normal before hand. The doctor will
clean the skin with antiseptic fluid and then pass
a very thin needle through the skin of the abdomen
into the uterus. A small amount of amniotic fluid
will be drawn off. During this time the ultrasound
is done to avoid injuries to the fetus and placenta.
The whole procedure will take about 10-15 minutes.
The test is done in the 14th and 18th week of pregnancy and results take several weeks. Risks include possible miscarriage (1%), infection, vaginal bleeding, leaking from the place where the needle went in, isoimmunization if mother is Rh+ and fetus is Rh-, and harm to the baby from the needle. These are rare, but they do occur.
Most
women say that the test is uncomfortable but not painful
and in most cases the thought if it is much worse than
the actual test.
You may go home as soon as the procedure is finished.
It is advisable to rest at least for one day and
you will be given two days off work. You should avoid
any heavy lifting or strenuous exercise.
The results will be available in two weeks. Rapid
results can be available in 2 days with newest techniques.
If an abnormality of any kind is discovered, your
doctor will tell you what it is and how it will affect
your baby. You will have the opportunity to discuss
the matter carefully. |
