A safer test for Down syndrome

By Carrie Johnson Weimar • Published: May 20th, 2011
Category: Health in a Heartbeat

Scientists have developed a new blood test that can help pregnant woman at risk for having a baby with Down syndrome avoid procedures that carry a risk of miscarriage.

The new test analyzes the mother’s blood for genetic material from both her and the fetus. That material is screened for signs that signal Down syndrome.

According to an article recently published in the British Medical Journal, the test is conclusive enough that it would eliminate the need for more invasive follow-up tests. These traditionally include amniocentesis and chorionic villus sampling. Because these tests have a risk of miscarriage, many expectant mothers opt not to have them.

The new blood test would be used if a mother is at risk for having a baby with Down syndrome due to her age or other factors, such as a genetic predisposition for the condition.

For the British Medical Journal study, scientists tested seven-hundred and fifty-three pregnant women. Using the blood screening test, the scientists found that eighty-six of these women were carrying a baby with Down syndrome. There were no false negatives, which means there wouldn’t be a need for a follow-up if a mother tested negative for Down syndrome.

Doctors say they may suggest a follow-up if the test results are positive for Down, both to confirm the finding and to screen for other birth defects. They also say the risks associated with amniocentesis and chorionic villus sampling are minimized when performed by a skilled obstetrician.

The down side: The new test is very expensive. But doctors say there’s good reason for hope. With all of the research being conducting in this area, many say it won’t be long before less invasive tests are the norm and procedures that carry a risk of miscarriage are a thing of the past.