New Prenatal Test for Down Syndrome

The possibility of Down syndrome is a worry for pregnant women, especially for those past their mid-30s. This condition is characterized by an abnormality on chromosome 21 and results in impaired cognitive function and some characteristic physical features. Until recently, the only way to get a prenatal diagnosis was with a test called amniocentesis. It involves using a needle to withdraw fluid from the amniotic sac and carries a small risk of complications. Now, a blood test has been developed that can diagnose almost 99 percent of infants with Down syndrome at an early stage of pregnancy. The test, called MaterniT21, is being rolled out in selected cities across the U.S.