More than 30 years ago, a 37-year-old friend of mine with an unplanned fourth pregnancy was told by her obstetrician that an amniocentesis was “too dangerous” and could cause a miscarriage. She ultimately bore a child severely affected by Down syndrome, which could have been detected with the test.
Today, my friend’s story would have a different trajectory. She would have a series of screening tests, and if the results suggested a high risk of Down syndrome, then an amniocentesis or chorionic villus sampling (C.V.S.) to make the diagnosis. She’d be given the option to abort the pregnancy.
In the future, a woman who decides to continue a Down syndrome pregnancy may also be offered prenatal treatment to temper the developmental harm to the fetus.
Prenatal diagnosis, today a routine part of obstetric care, has made great strides since the mid-1970s and is now on the cusp of further revolutionary developments.
In the nearly four decades since amniocentesis became widely accepted, new techniques have gradually improved the safety and accuracy of prenatal diagnosis. Prenatal tests for more than 800 genetic disorders have been developed. And the number of women who must undergo amniocentesis or C.V.S. has been greatly reduced.
The newest screening test, highly accurate and noninvasive, relies on fetal genetic fragments found in the mother’s blood. Available commercially from four companies, this test is so accurate in detecting Down syndrome that few, if any, affected fetuses are missed, and far fewer women need an invasive procedure to confirm or refute the presence of Down, according to studies in several countries.
The new test, done late in the first trimester of pregnancy, can also detect other genetic diseases, like extra copies of chromosomes 13 and 18, and a missing sex chromosome. It is not yet approved by the Food and Drug Administration, however, and the American College of Obstetrics and Gynecology currently recommends it only for women at high risk for having a baby with a chromosomal abnormality.
But any woman can get the new screening test if her doctor orders it and she is willing to pay for it herself, according to Dr. Diana W. Bianchi, a neonatologist and geneticist at Tufts University School of Medicine. Dr. Bianchi, who serves on the advisory board of a company selling fetal DNA tests, said she expects these tests will soon become routine for all pregnant women because, in addition to their “extraordinary accuracy” in detecting a Down syndrome pregnancy, they can be done earlier than other tests, and reduce costs and the risk of complications.
Down syndrome, which occurs in about one in every 700 births in the United States, is by far the most common chromosomal abnormality. It causes physical and intellectual disabilities that range from mild to severe.Translation = We know more about the kid in the womb so if we want to kill it, we can be appropriately informed. If you are over 35, ever wonder why you see way less people with Down Syndrome walking around today than when you were a kid? The answer should be chilling.
