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 or problems with previous pregnancies. The best
time to have genetic screening is before a pregnancy,
but it can also be done at specific time points during a pregnancy.
There are 2 general types of genetic screening. Testing for a specific gene can be done when an inherited disorder runs in the family or a specific disorder is suspected. A screen for many genetic defects can be done when there are non-specific findings.
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 healthcare provider may recommend genetic screening:
- Mother or father has family members with inherited disorders
- Mother is 35 years old or older at the child's birth
- 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 healthcare provider may screen for include:
fibrosis—Caused by two defective genes, affecting the lungs and pancreas.
Tay-Sachs disease—A brain
disorder, which is more common in people of Eastern European (Ashkenazi) Jewish descent, that causes early death.
Thalassemia—A type of anemia caused by abnormal red blood cells. The condition is more common in people from southeast
Asia, China, and Mediterranean countries, such as Greece and Italy.
Hemophilia—A blood clotting disorder.
Sickle cell anemia—More common in African Americans of sub-Saharan origin, affecting the red blood cells.
- Any possible genetic defect that may affect your child in the future, such as BRAC mutations that increase the risk of breast and ovarian cancers.
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 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
What Takes Place During the Genetic Screening Process?
During the genetic screening process, your healthcare provider
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. The family history may help determine which genetic tests will be needed.
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
- Chorionic villus sampling (CVS) to check for chromosomal
to check for chromosomal abnormalities
After the screening and tests, your healthcare provider 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 healthcare provider should
provide you with lots of information about treatment options so
that you can make informed choices.
American Congress of Obstetricians and Gynecologists
Women's Health—Department of Health and Human Services
Society of Obstetricians and Gynaecologists of Canada
Women's Health Matters
Genetic counseling. American Pregnancy Association website. Available at: http://americanpregnancy.org/getting-pregnant/genetic-counseling. Updated September 2, 2016. Accessed October 25, 2016.
Routine prenatal care. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated June 22, 2016. Accessed October 25, 2016.
Routine tests in pregnancy. American Congress of Obstetricians and Gynecologists website. Available at: http://www.acog.org/~/media/For%20Patients/faq133.pdf?dmc=1&ts=20121217T1134335563. Updated January 2016. Accessed October 25, 2016.
Screening for birth defects. American Congress of Obstetricians and Gynecologists website. Available at: http://www.acog.org/~/media/For%20Patients/faq165.pdf?dmc=1&ts=20121217T1134388121. Updated September 2016. Accessed October 25, 2016.