Lee CooperArlington, Mass.

To the Editor:

As a practicing reproductive geneticist for almost 20 years, I was pleased to read this critical piece on noninvasive prenatal testing, or NIPT. It is important to understand its history to make sense of our current situation.

A highly accurate prenatal test for Down syndrome had been the holy grail for decades. The goal was to help pregnant patients avoid a risky procedure chorionic villus sampling (C.V.S.) or amniocentesis. Older studies from the 1980s showed a risk of miscarriage from these procedures ranging from 1 in 100 to 1 in 200. However, recent studies show these procedures are quite safe, with a risk of pregnancy loss of approximately 1 in 1,000 for most patients.

If these definitive tests are relatively safe, why has noninvasive prenatal testing become the first-line test for most patients despite their flaws? The answer: direct to consumer marketing and direct to obstetrician marketing.

Marta C. KolthoffPittsburghThe writer is director of medical genetics at West Penn Hospital.

To the Editor:

This article is a very important in-depth look at the misleading and ambiguous results that come from prenatal testing. As a fourth-year medical student, I thought myself abundantly prepared for the terrain of prenatal testing during my first pregnancy. I navely took a prenatal test, with no prior counseling on the false positivity rates. When I received a high-risk result via a message from my doctor, I was stunned.

Even with my personal connections to genetic counselors and familiarity with the science behind these tests, after reading the fine print of the test, visiting the test makers website and many hours of reading scientific papers, I was left confused. After waiting until 16 weeks for an amniocentesis and another two weeks for the results, I was told the test had become contaminated and would need to be rerun.

Thus, after more than 20 weeks I am still living in the unknown, in an area where we want answers that technology is not yet sophisticated enough to give. It is imperative that practitioners educate patients about these limitations before testing.

Penina KriegerNew York

To the Editor:

I am concerned by the appearance of this article at a time when public trust in medical screening is more important than ever. Some readers might see this article and say to themselves, I guess I cant trust any medical screens now. That would be the wrong conclusion.

Continue reading here:
Opinion | The Benefits and Pitfalls of Prenatal Genetic Tests - The New York Times