Paul Tuns:
The New York Times ran a long article on Jan. 1: “When they warn of rare disorders, these prenatal tests are usually wrong.” The examination by the New York Times found that non-invasive blood tests taken in early pregnancy that look for missing chromosomes are wrong 17 out of 20 times when they indicate a genetic problem other than Down syndrome. In 2017, the British Journal of General Practice found that for Down syndrome, the most common genetic anomaly tested prenatally, non-invasive prenatal testing (NIPT) was more than 99 per cent accurate. But as the Times discovered, for the other most common anomalies screened, a test that shows a child at risk of having a genetic anomaly is more likely to be wrong than right.
Pregnant mothers prefer the non-invasive procedures over the more accurate but often painful procedure in which a long needle is inserted to either extract some amniotic fluid or a placenta sample. According to protocols suggested by the American College of Obstetricians and Gynecologists, those tests should follow the initial blood screening, because of their greater accuracy but they are more expensive, more invasive, and carry a small risk of miscarriage (0.5 per cent or one in 200 tests). The chance of having a child with a chromosomal anomaly is one in 600 or about 0.16 per cent. Some screenings are done for cases so rare – Jacobsen syndrome affects just one in 100,000 births, for example – that some experts wonder why they are screened at all. Dr. Diana Bianchi studies prenatal test screenings for the National Institutes of Health and she told the Times that she has never seen a case of Jacobsen syndrome in 20 years of practicing genetics.
However, the Times investigation confirms what peer-reviewed research has long indicated: expectant mothers are not properly presented with information surrounding the screening and many women choose to end their pregnancy through abortion when informed that their child is at risk of a plethora of genetic diseases or ailments without confirming the screening result.
Over the past decade, major medical companies such as Labcorp, Natera, Quest Diagnostics, and Sequenom have found a lucrative market delivering “peace of mind” to expectant mothers by offering a screening service to detect a risk of various rare genetic anomalies. The Times estimates that a third of pregnant women use screening tests to detect genetic problems in their preborn children.
The conditions that are ostensibly detectable through these NIPT blood screenings are supposedly revealed by missing pieces of chromosomes called microdeletions or extra or missing copies of entire chromosomes, and many of the ailments have symptoms such as intellectual disability, heart defects, shortened lifespans, or high infant morality rates that many parents would prefer to avoid by eliminating the less-than-perfect preborn child.
The Times reporters interviewed researchers and analyzed data from multiple studies for the five most common microdeletion tests performed: DiGeorge syndrome (causes heart defects and delayed language learning); 1p36 deletion (causes seizures and intellectual disability); Cri-du-chat syndrome (can cause difficulty walking and delayed speech development); Wolf-Hirschhorn syndrome (causes seizures, growth delays, and intellectual disabilities); and Prader-Willi syndrome (causes seizures and an inability to control food consumption).
The Times investigation found that the number of false-positives – that is a screening result that suggests a genetic anomaly – range from 80 per cent for Cri-du-chat syndrome and 81 per cent for DiGeorge syndrome to 93 per cent for Prader-Willi syndrome. For every 15 correct screenings for one of these five syndromes, there were 85 incorrect false-positives.
The Times reported that about six per cent of tests include the “full panel of microdeletions” and they found about eight true-positives and between 17 and 135 false-positives. In other words, in the best-case scenario, there were twice as many false-positives as true-positives.
Many women will choose to have an abortion after being told that their child is at risk of having one of these syndromes; while there are hundreds of microdeletion syndromes, most samples are only tested for five to seven genetic anomalies; The Times reports, “Six per cent of patients who screened positive obtained an abortion without getting another test.
While, the Times talked to several women who nearly had abortions after being told the screening suggested their babies were at high risk of a genetic anomaly that subsequent testing revealed to be false-positives. The Times reported that one woman almost had an abortion when the screening showed her child might have Turner syndrome, which can cause infertility in the child. Other studies have shown false-positives in 74 per cent of Turner syndrome indications. The Times reports that Allison Mahilich had a screening test that provided a false positive and she would have had an abortion before Indiana’s 22-week abortion ban if diagnostic tests, hurriedly taken so she could have the abortion, had not shown her child to be healthy.
The American College of Obstetricians and Gynecologists says that it should be explained that the NIPT screenings are not diagnostic tests but a preliminary finding that should be followed up with a more invasive procedure to confirm the finding. When this is done, the majority of time, the diagnostic test proves the screening was a false-positive.
The genetic testing companies issued statements in response to the Times story saying that women should always have a follow-up diagnosis because the test is merely a screen to determine high-risk patients. But a 2016 study by Laura C. Colicchia et al published in the Journal of Obstetrics and Gynaecology found that although nine in ten doctors offered genetic screening at the initial visit for a pregnancy, few physicians spent much time with patients discussing what the screenings actually were – and were not – with most doctors spending less than two minutes discussing the test with patients. It found that more than half of physicians did not clarify the difference between a screening and a diagnostic test to the mother and most preferred to describe “high-risk” or “low-risk” than actually talk about actual probabilities. The authors of the study reported, “most health care providers’ counseling did not adhere to College recommendations.”
The American College of Obstetricians and Gynecologists says that all pregnant women should be offered screening in the first or second trimester and that doctors specifically address detection and false-positive rates, the advantages, disadvantages and limitations of the screening tests, and the option of diagnostic testing.
The Colicchia study found many physicians who order the screenings are not aware themselves of the issue of false-positives, let alone the scope of errors.
Despite the high rates of inaccuracy for these screenings, the promotional literature provided by the medical screening companies describes the findings as “reliable” and “highly accurate” in order to offer “total confidence” and “peace of mind” for mothers curious about the health of their preborn babies. The Times discovered that many companies only highlight numbers for their most accurate screenings. Alberto Guitierrez, a former director of the Food and Drug Administration, told the Time that “the information they provide is misleading.”
Misleading or not, the consequences are often tragic. The Times talked to a number of women who almost had abortions but changed their minds and had more accurate but invasive tests after the original shock of the screening results indicated a problem. Ann Farmer, writing in MercatorNet, said “pregnant women are seldom in the mood for lectures on Bayesian statistics” and many will react without full knowledge of what they are doing: “if they are dismayed by the news, they are likely to have an abortion.” Farmer describes prenatal infanticide following prenatal screening as “lethal prebirth discrimination against the innocent.”
The Tablet reported that one woman, Debra Gleeson, was screened before the birth of her son and was told he would be born with a rare genetic disorder. The screen was wrong, but Gleeson complained that she felt pressured to have an abortion by her physician. She told the paper, doctors told her it was the only option for treatment “because he’s going to die anyway.”
Dr. Tara Sander Lee told the Tablet that physicians need to present their findings not only in more accurate ways but in more life-affirming ways so that pregnant mothers do not feel that their only choice is to have an abortion. She said that often doctors describe worst-case scenarios and focus on the difficulties rather than moments of joy that a newborn baby – even one less than fully healthy – can provide parents. Sander Lee said many doctors do not provide information about treatments or supports for children with genetic anomalies.
William Lori, Archbishop of Baltimore and pro-life chair of the U.S. Conference of Catholic Bishops, said abortion is often presented as “better for the baby, and that’s a completely upside-down way of thinking.” Mary Szoch and Joy Zavalick of the Center for Human Dignity at Family Research Council, wrote in The Federalist: “Genetic screening exploits parents’ fear of the unknown and perpetuates the false mindset that children are only a blessing when they lack a diagnosis.”
The Food and Drug Administration does not regulate the use of prenatal screening. In January, nearly 100 Republican members of Congress, sent a letter to Janet Woodcock, Acting Commissioner U.S. Food and Drug Administration asking her to provide information on data the FDA has on the efficacy of prenatal screening and why screening tests are not regulated like other common medical technologies. The lawmakers argue that “there must be proper oversight of these new technologies to protect vulnerable populations like persons with disabilities, pregnant mothers, and their unborn children.”
Szoch and Zavalick support the Republican Congressmen’s attempts to get answers from the FDA: “If the tests are more likely to be wrong than right, and the companies offering the tests are profiting by stealing parents’ peace of mind — and possibly the lives of their unborn children — then the logical conclusion is to refuse to play their game. As the referees of the medical testing industry, it is time the FDA blows the whistle.”
