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Genetic Counseling
The world of genetic testing is
complicated. Genetic counselors
help couples understand the
complex genetic information,
discuss the implications of such
testing for the couple and their
family, organize the testing,
provide in-depth explanations of
the results, and guide and support
the couple to make informed
decisions.
Types of Tests
There are two kinds of tests that
can be done in pregnancy:
1. Screening Tests: These
can tell you if you are at a risk of
having a baby with birth defects.
These tests will not give you
definite information about the
fetus.
These include a combination
of blood tests and ultrasound
examination and are part of the
routine pregnancy check-ups.
2. Diagnostic Tests: These
can tell you if the fetus has a defect.
These include:
Chorionic Villus Sampling
(CVS) (at 11 to 12 weeks)
In this test a small sample is taken
from the placenta. The sample
from the placenta can be used for
genetic testing. One woman in one
hundred (one percent) could have
a miscarriage as a result of this test.
Amniocentesis
(at 15 to 18 weeks)
A sample of the amniotic fluid that
surrounds the baby is collected
and can be used for genetic
testing. Amniocentesis has a one
in two hundred risk of causing a
miscarriage.
Ultrasound scans
(at 18 to 20 weeks)
This second trimester scan is used
to identify physical and structural
abnormalities including Spina
Bi da, heart and limb defects.
Non-Invasive Prenatal Diagnosis
(at 10 to 24 weeks)
Non-
invasive
prenatal
testing is a
relatively
new, and
sophisticated blood test that
examines fetal DNA from the
mother’s blood to determine
whether the fetus is at risk of
Down Syndrome, extra sequences
of chromosome 13 (trisomy 13),
extra sequences of chromosome 18
(trisomy 18) or a sex chromosome
abnormality, such as Turner’s
syndrome. The testing can also be
used to determine a fetus’ sex and
rhesus (Rh) blood type.
Email:
The Tests
The information from the
carrier screen test can help
couples make decisions about
their reproductive options
and their child’s medical care
that may be required.
The carrier screen would cover
hundreds of genetic diseases
including, but not limited to,
Alpha and Beta Thalassemia,
Sickle-cell anemia, Spinal
Muscular Dystrophy, G6PD
and so forth. In fact, many
of the diseases included can
shorten life expectancy and/
or cause physical/cognitive
impairment.
Reproductive Options
If a couple is found to be
carrying a disease-causing
mutation, their reproductive
options include:
• Screening embryos created
by in-vitro fertilization (IVF)
before pregnancy
• Continuing naturally
with family planning and
pregnancy
• Testing the pregnancy via
Chorionic Villus Sampling
(CVS) of Amniocentesis
• Adopting a child
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Mar/Apr 2015