New York Times study finds some prenatal testing incorrect most of the time

A new study conducted by The New York Times is raising serious questions about the common practice of prenatal testing. According to the report, screenings of pregnant women for rare genetic anomalies produce false results about 85% of the time.

The consequences can be dire, as many parents do not undergo follow-up testing after receiving a diagnosis for their unborn baby. A 2014 study found that as many as 6% of patients who had received a positive in their initial screening went ahead and had an abortion without first testing to confirm the result.

Follow-up testing itself can also result in the death of the fetus. Those who choose to confirm their positive results by testing amniotic fluid or placental tissue risk suffering a miscarriage.

Prenatal testing has become a major industry over the course of the last decade, with more than one third of pregnant women in America opting to undergo blood tests to screen for developmental problems. According to the report, the initial tests that screened for Down syndrome were more accurate than the newer tests offered today, which promise to screen for rarer conditions.

The Times study found that five of the tests offered by testing companies are incorrect from 80% to 94% of the time. A test for a very rare condition (1 in 20,000 births) called Prader-Willi and Angelman syndromes, which causes seizures and an inability to control food consumption, was wrong 94% of the time.

So why test for these extremely rare conditions if the results are wrong far more than they are right? Some researchers says the laboratories stand to make a lot of money the more they test.

“It’s a little like running mammograms on kids,” Mary Norton, an obstetrician and geneticist at the University of California, San Francisco told The New York Times. “The chance of breast cancer is so low, so why are you doing it? I think it’s purely a marketing thing.”

In interviews with 14 patients who received false positives, The New York Times found that 8 of them were never told that it was possible to get a false positive. Five of them “recalled that their doctor treated the test results as definitive.”

There is no government oversight for these tests, according to the report. The FDA “considered regulating these tests a decade ago, but backed away.”

While the article does not report on the tragedy of babies aborted solely because of medical diagnoses, it does report on instances where mothers decided to terminate their pregnancies because of false positives:

“Three geneticists recounted more recent examples in interviews with The Times. One described a case in which the follow-up testing revealed the fetus was healthy. But by the time the results came, the patient had already ended her pregnancy.”

Read the entire report here.