Simple, early blood test offers insights into fetal health
SAN JOSE, Calif. _ Raising the prospect of a world without birth defects, a Stanford-created blood test that can detect Down syndrome and two other major genetic defects very early in a woman's pregnancy will be available next week.
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.
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