The simple blood test spares women the risk and heartache of later and more invasive tests like amniocentesis.
But it has startling social implications -- heralding a not-distant future when many fetal traits, from deadly disease to hair color, are known promptly after conception when abortion is safer and simpler.
The $1,200 test, which analyzes fetal DNA in a mother who is 10 weeks pregnant, is being offered to doctors March 1 by Verinata Health, a biotechnology company in Redwood City, Calif. It licensed a technique designed by Stanford biophysicist Stephen Quake.
"It's a game changer," said Stanford University law professor Hank Greely, who studies the legal and ethical implications of emerging technologies. The controversy over abortion "is about to be hit by a tsunami of new science."
There are two converging trends, Greely said. "We've got politicians running for president who are really trying to whack away at reproductive rights at a time when the science is about to vastly expand the information that parents have about their fetus."
A similar test is already available from the San Diego company Sequenom, and at least two other San Francisco Bay area companies plan to offer noninvasive prenatal genetic testing.
The market is huge: 4.5 million U.S. births a year, of which an estimated 750,000 are "high risk," due to age or family history.
The current crop of tests only seeks major abnormalities on three chromosomes: 13, 18 and 21. They can also tell whether a fetus is a boy or girl.
But perhaps within the next five years "it seems likely that a simple blood draw from the pregnant woman will be able to provide genetic results for a fetus about not just Down syndrome," Greely said, "but cystic fibrosis, sickle cell anemia, Tay-Sachs disease and a host of other diseases."
"I don't think many parents would abort a fetus because it is blond or because it doesn't have the best genes to be an athlete," Greely said. "But I do think it will greatly increase the number of fetuses aborted for mainly medical reasons, and sometimes for nonmedical reasons, like sex because it is so much easier to find out. And you find out faster.
"You can make the decision before anyone else really knows you are pregnant -- and when abortions are less complicated, medically and socially."
The day may come, experts say, when parents are spared the trauma of a baby who perishes at birth -- or enters a life filled with pain or profound disability.
The test's effectiveness was reported Thursday in the long-awaited findings of a Verinata-sponsored clinical trial published in the journal of the American Congress of Obstetrics and Gynecology.
For women with insurance coverage, Verinata said it would provide documentation to support a claim. But in cases where the claim is denied, or if a woman is uninsured, it will negotiate a discount, it said.
It accurately detected all 89 cases of Down syndrome in 532 maternal blood samples. It also detected 35 of 36 cases of Edwards syndrome and 11 of 14 cases of Patau syndrome -- two far more devastating chromosomal abnormalities.
The disease occurrence was high because women were selected for the research trial if they were considered high risk due to advanced age, if their fetus tested positive through conventional tests for chromosomal defects, or if they previously had a baby with chromosomal defects. The test predictions were compared to the actual birth outcomes.
Quake got interested in this approach in 2004 when he first became a father, "and I saw the invasive tests to my wife and unborn child. I thought: 'There's got to be a better way.'''
He stumbled across a 1948 discovery about free-floating fetal DNA in maternal blood -- called "cell free DNA." But scientists then could not measure the genetic material precisely enough to make a diagnosis.
The new test counts the millions of DNA molecules from both the mother and baby and can detect excessive genetic material that signals a birth defect.
A woman goes to the doctor's office for the a simple blood draw. In eight to 10 days, the doctor will know whether any of the three chromosomes tested is normal or abnormal.
Katie Fischl Fuller, of Santa Clara, whose baby is due in March, said she would have welcomed the test.
"Amniocentesis is horrible. It's very invasive," she said. "A needle is inserted through your stomach into the uterus, which risks injuring the baby. Risk of miscarrying is 1 in 250 or 300 ... when you can feel the baby moving, and you've already connected."
Members of the anti-abortion community also said they would welcome the test if it is used to give parents time to prepare for the birth of a handicapped infant.
"But if it's a search-and-destroy mission, where the baby is aborted, we are not in favor of it," said Cecelia Cody, administrative director of California Right to Life in Walnut Creek. "I don't think the world is a better place without these babies. It's getting close to Nazi eugenics, isn't it, to decide who lives? If a baby is shown to have a cleft palate, do they die?
"It is difficult to know how people will act on this information," said Michael Katz, medical director of the March of Dimes.
Although the tests "are no longer experimental ... it is the future. Soon all the other tests will be secondary."
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