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.
