Early detection of Down Syndrome

By HSC Staff Writer • Published: February 10th, 2006
Category: Health in a Heartbeat

Each year Down syndrome… one of the most common genetic birth defects… affects about five-thousand babies born in the United States. Prenatal screening for the chromosomal disorder has been available for about thirty years. But none of the traditional tests are one-hundred-percent accurate. And none can be done until the second trimester of pregnancy.

Recently researchers announced a new, reliable screening method that’s more accurate… and that can be done as early as eleven weeks after conception. The method… which uses two blood tests and an ultrasound exam… provides women information they need to decide if they want follow-up testing to confirm the Down syndrome diagnosis.

Currently, women… especially those at high risk because of age or family history… are offered a blood test called the quadruple test at about sixteen weeks into their pregnancy. If they test positive, they can then opt for amniocentesis. In this procedure, which carries a small risk of miscarriage, a small amount of amniotic fluid is withdrawn and then analyzed to detect genetic abnormalities in the fetus.

In an eight-year, fifteen-million-dollar study of thirty-eight-thousand U-S women, researchers found the new screening method identified eighty-seven percent of Down syndrome babies when used at eleven weeks. The later quadruple test identified eighty-one percent. Together the two tests found ninety-five percent of cases.

While no test is one-hundred-percent accurate, the new approach offers earlier, newfound reliability, and can give parents peace of mind sooner… or at least more time to plan.