NEW YORK — By this time next year there may be an alternative prenatal test for Down syndrome that offers accurate results as early as nine weeks into the pregnancy.
For years, many women have undergone a blood or ultrasound test that indicates a heightened risk of Down syndrome, followed by a procedure to make a firm diagnosis by capturing DNA from the fetus.
Usually, it is a needle procedure, called amniocentesis, done almost four months or more into the pregnancy. Sometimes it is an earlier test called chorionic villus sampling, which collects a bit of tissue from the placenta. Both pose a tiny but real chance of miscarriage.
But companies are racing to market a more accurate blood test than those available now that could spare many women the need for the other two tests. It would retrieve fetal DNA from the mother’s bloodstream, and the answer could come before the pregnancy is obvious to others.
Current screening has already reduced the number of babies born with the syndrome, which now stands at about 6,000 each year in the United States, or about 1 in every 691 babies, said Dr. Brian Skotko, a Down syndrome specialist at Children’s Hospital Boston.