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Genetic Screening Tests for Women 35 or Older

Noninvasive Prenatal Diagnosis

This new blood test, also called cell-free DNA testing, is used to show whether you are at risk for having a baby with chromosome problems. Because it's done by using a sample of your blood, it's less invasive than amniocentesis or CVS.

The test is done between 10 and 22 weeks of pregnancy. It finds DNA from your baby floating around in your blood. The result determines the chance that your baby could be born with Down syndrome, trisomy 18, or trisomy 13. 

Noninvasive prenatal diagnosis can detect about 99% of Down syndrome and trisomy 18 cases, which is much better than other blood tests. The majority of  trisomy 13 cases can also be detected with this test.

If the test shows an increased risk for chromosome problems, your doctor may recommend CVS or amniocentesis to confirm the diagnosis.

Because this is a new test, not all insurers cover it. Check with your insurance company to see whether the cost of the test will be covered.


WebMD Medical Reference

Reviewed by Traci C. Johnson, MD, FACOG on August 22, 2014

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