When Ramona Burton became pregnant with her second child this year, the 37-year-old Upper Marlboro, Md., woman knew that her age put her baby at an elevated risk for Down syndrome, even though screening with ultrasound and standard blood tests raised no warning flags.
Burton and her husband didn't want to risk amniocentesis, the gold standard for prenatal diagnosis, because it carries a small chance of miscarriage. So when her doctor offered an alternative — a new test that requires only a sample of the mother's blood — they leapt at it. In less than two weeks, they got the news: no Down syndrome. The baby, a boy, is due next month.
Three versions of this test, which can be performed as early as 10 weeks into a pregnancy, have come onto the market since December.
Tens of thousands of women have used them, according to the companies that sell the tests. But they are not subject to regulation by the Food and Drug Administration, and questions have been raised about a technology whose accuracy and role are still being assessed. As a result, no major insurance company has yet agreed to cover the tests, whose list prices range up to $1,900.
New medical technologies often challenge a health-care industry grappling with pressures to control costs. It's not yet clear whether the new tests will cut costs and miscarriages by reducing invasive prenatal diagnostic procedures such as amniocentesis or inflate costs because they're used by women who probably would never have opted for amnio because of miscarriage fears. (The established tests are performed about 200,000 times annually in the United States and cost roughly $2,500 in the Washington area.)
With the new tests, fragments of fetal DNA extracted from the mother's blood sample are checked for increased amounts of material from chromosomes 21, 18 and 13, a sign that the fetus carries three instead of the normal two copies of those chromosomes.