Inaccurate prenatal tests could prompt mothers across the country to needlessly abort their healthy unborn fetuses, a startling new report claims.
The New England Center for Investigative Reporting found that some women are terminating their pregnancies based on a test result for a genetic condition — even though the center’s study shows that the tests can be wrong 50% of the time.
Shockingly, the group also found that the rate of false positives increased as the conditions became rarer.
Noninvasive prenatal testing — also known as cell-free DNA testing — looks at DNA in a baby’s placenta for conditions like Down syndrome and other chromosomal disorders.
The simple tests can be performed just nine weeks after pregnancy begins — and boast accuracy rates of 99%. But that number is misleading, experts say, because it does not take into account false positives.
An estimated 450,000 to 800,000 women have undergone these tests in the U.S., according to the Boston Globe.
By 2019, it’s expected to be a $3.6 billion industry worldwide.
But the results should be confirmed with another, more invasive test before women abort a pregnancy, experts say.
“Nobody should do anything based on the screening test,” cautioned Dr. Iffath Hoskins, a obstetrics and gynecology professor at NYU Langone Medical Center. She said aborting a fetus after one test is like getting a hysterectomy after one Pap test.
A recent study of 356 women by Natera, which makes the Panorama prenatal test, showed that 6.2% terminated their pregnancy based on noninvasive test results alone.
Illumina, which makes the Verifi test, told the Daily News that it “has always emphasized the need for confirmatory testing.”
One of the problems is that test results are often misread. Two Boston obstetricians recently sent cell samples from two nonpregnant women to five testing companies — and three out of the five companies said the women were carrying healthy baby girls.
Sometimes, the test can also produce a false negative — declaring a fetus illness-free, when in reality it has a genetic disorder.
Belinda Boydston, 43, of Chandler, Ariz., got pregnant through in-vitro fertilization and was due this January. Her ob-gyn saw some cysts on her baby’s brain and recommended that Boydston get the Harmony test by Ariosa Diagnostics. She could have opted for an amniocentesis later in her pregnancy, but it came with miscarriage risks.
The test came back negative for any disorders. But her son Hunter was born with trisomy 18 and died only four days after being born.
“I remember saying, ‘Well, the doctors must be wrong, because this is what the result said,’ ” Boydston recalled to the Daily News.
False negatives, though devastating, are rare, said Dr. Trilochan Sahoo, director of cytogenetics at California-based CombiMatrix, a lab that does invasive prenatal testing like amniocentesis.
Sahoo encourages all women to carefully interpret the results of any test, while Elizabeth Daley, a reporter with the New England Center for Investigative Reporting, said the tests have come a long way since earlier ones.
“You have to understand the limitations and you have to realize they’re screening tests and not diagnostic,” Daley added.
With Beth Stebner
