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 on having a baby might be concerned about illnesses in the family that their child might inherit. 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.
Who Should Have Genetic Screening?
Common reasons for having genetic screening include:
- You will be 35 years old or older when you deliver your baby.
- You already gave birth to a child with a hereditary disease or birth defect.
- You have had stillbirths or several ]]>miscarriages]]> .
- You have an abnormality such as too much or too little serum alpha fetoprotein (AFP).
You have a family history of
the following conditions:
- ]]>Tay-Sach's disease]]> is a brain disorder, which is more common in people of Eastern European (Ashkenazi) Jewish descent, that causes early death.
- ]]>Thalassemia]]> causes abnormal red blood cells. The condition is more common in people from southeast Asia, China, and Mediterranean countries, such as Greece and Italy.
- ]]>Hemophilia]]> 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 Blacks 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 mental retardation in the family. Make a record of any of the following personal information:
- Exposure to environmental hazards before or during pregnancy (such as ]]>x-rays]]> or other radiation; chemicals used at work, home, or with hobbies)
- 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 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. Examples of genetic screening tests given during pregnancy include:
- Blood tests to check the levels of alpha fetoprotein (at 15 to 19 weeks of pregnancy), with possible follow-up tests to look for neural tube defects
- ]]>Ultrasound]]> scans to check for birth defects of the brain, heart, spine, arms, legs, and other organs (after the 15th week of pregnancy)
- Chorionic villus sampling (CVS) to check for chromosomal abnormalities (between the 9th and 12th week of pregnancy)
- ]]>Amniocentesis]]> 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.
Women's Health Matters
Genetic counseling. March of Dimes website. Available at: http://www.marchofdimes.com/pnhec/4439_15008.asp. Accessed June 17, 2009.
Last reviewed January 2009 by ]]> Jeff Andrews, MD, FRCSC, FACOG]]>
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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