What Is Genetic Screening?
Genetic screening is a process used to determine a child's risk
of inheriting certain diseases or birth defects from his or her
parents. Couples planning to have a baby might be concerned about
illnesses that have occurred in family members. The best
time to have a genetic screening done is before you get pregnant,
but it can also be done during your first prenatal visit or later
in your pregnancy.
There are several tests that look for different genetic disorders.
Who Should Have Genetic Screening?
Keep in mind that genetic testing is not done for every pregnancy. Some have an increased risk of having a child with a genetic condition. Here are some common reasons your doctor may recommend genetic screening :
- Mother or father has family members with inherited disorders
- Mother is 35 years old or older when you deliver your
- Previous child with a hereditary disease or
Previous stillbirths or several
- Abnormalities in the pregnancy such as too much or too little serum
alpha fetoprotein (AFP).
Conditions that your doctor may screen for include:
- Tay-Sach's disease
is a brain
disorder, which is more common in people of Eastern European (Ashkenazi) Jewish descent, that causes early death.
causes abnormal red blood cells. The condition is more common in people from southeast
Asia, China, and Mediterranean countries, such as Greece and Italy.
is a blood clotting disorder.
- Cystic fibrosis, caused by two defected genes, affects the lungs and pancreas.
- Sickle cell anemia, which is more common in African Americans of sub-Saharan origin, affects the red blood cells.
What Should I Know Before Having Genetic Screening?
You should find out about the medical history of your family,
including hereditary diseases in your mother's and father's
families. If possible, ask your parents and your partner's parents
about any abnormalities, disabilities, or
family. Make a record of any of the following personal
Exposure to environmental hazards before or during pregnancy
or other radiation; chemicals used at work, home, or with
- Any prescription or nonprescription drugs you took before
pregnancy or before you knew you were pregnant
- Any history of alcohol or drug use
What Takes Place During the Genetic Screening Process?
During the genetic screening process, your doctor
will ask you and your partner for a detailed family history of
diseases, disorders, and birth defects. You may be given blood
tests. If you are already pregnant, you might be given tests to
examine the chromosomes and condition of the fetus. Examples of
genetic screening tests given during pregnancy include:
- Blood tests to check the levels of alpha fetoprotein, with possible follow-up tests to look
for neural tube defects
scans to check for birth defects of the brain,
heart, spine, arms, legs, and other organs
- Chorionic villus sampling (CVS) to check for chromosomal
to check for chromosomal abnormalities
After the screening and tests, your doctor will
discuss the results with you and make recommendations about any
treatment that may be beneficial. Treatment is a personal choice
that is left entirely up to you. Your doctor should
provide you with lots of information about treatment options so
that you can make informed choices.