Sometimes diagnostic testing is suggested
to you by your doctor for reasons
outlined below. It is important that
you know what you are in for. CVS
or chorionic villus is one such invasive
test. It is usually carried out during
the 1st trimester if your doctor suspects
the fetus having any chromosome or
biochemical abnormalities. This diagnostic
test involves a sample or biopsy of
the chorionic villi (tiny finger like
projection on the placenta). These
cells contain genetic information
that can analyse chromosomal problems
and inform you on your baby's gender
as well if you like. This test is
used to determine specific conditions
like:
• Down's syndrome
• Cystic fibrosis
• Thalassaemia
• Certain types of hemophilia
• Duchene's muscular dystrophy
• Turner syndrome
• Sickle cell anemia
• Fragile-X syndrome
• Phenylketonuria
• Antitrypsin deficiency
Who is
the likely candidate for CVS testing
during pregnancy
You may qualify for CVS if you:
1. are over 35
2. already have or had a child affected
by one of the conditions listed above
3. have a family history of one of
these conditions
4. have an 'increased risk' blood
test result
5. have a clue from the nuchal fold
test that all is not right with the
fetus
Although this test can detect chromosomal
defects, don't count on it to test
for Spina bifida. The safe period
for testing is between weeks 10 and
12; CVS is able to indicate the presence
of a problem much earlier than the
other popular diagnostic test called
amniocentesis. This test can be conducted
in two ways: transvaginal and transabdominal.
There isn't really much difference
as both involve the ultrasound and
the insertion of a catheter either
through the vagina or abdomen. However
check with your doctor on which method
will be suitable for you. (Factors
include the preference of your doctor,
the position of the placenta and how
advanced are you in your pregnancy).
The Down
side of CVS is
• the main risk involved, which
is miscarriage. According to some
experts there is up to 30% chance
of miscarrying
• it is not always accurate.
If cells are inaccurately taken from
the site, this test won't be able
to offer any indication on the health
of the unborn child.
• some abnormalities in chorionic
tissues don't surface in the fetus.
It is therefore important to seek
a second opinion of any negative report
before you decide on anything.
• it can be uncomfortable or
even painful especially if it is done
via the abdomen. Done vaginally, the
sensation can be compared to a pap
smear.
The Up
side of CVS is
• the procedure is short, about
10-20 minutes
• it can be performed earlier
and therefore you get to know the
results sooner
• results take about a week
and in some cases as early as 2 days
• since the preliminary results
come earlier it is often less painful
emotionally and physically easier
if you decide to terminate a pregnancy
involving a baby with an abnormality
The procedure
itself
• you will need a full bladder
• you will be given an anesthetic
if its transabdominal method
• you will need to lie still
while the technician uses an ultrasound
to see exactly where the baby is inside
the sac
• a tube is then inserted either
through your vagina or directly into
your abdomen.
• The fresh cells are examined
right away and some answers can be
obtained within 48 hours after a CVS
After the
CVS test
• Rest for at least 24 hours
and take it easy for 3 days
• Expect to feel cramping pains
and slight vaginal bleeding for 2
- 3 days
• Report to your doctor immediately
if the blood loss is severe or goes
beyond 3 days
• Also contact your doctor if
you experience loose clear fluid as
this may be amniotic fluid
• If everything is normal, you
will receive the results through the
post
• You can request that your
report not state the gender findings;
notify your doctor beforehand.
