Over the past year, several companies have unveiled non-invasive prenatal tests designed to detect certain genetic conditions by analyzing fragments of fetal DNA contained in a pregnant woman's blood. Unlike the genetic screening currently offered to women early in pregnancy, which is used to calculate the fetus's risk of developing a particular genetic disorder, non-invasive prenatal testing (NIPT) is diagnostic, and can tell an expectant mother with an extremely high level of accuracy whether or not her fetus actually has trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome), or trisomy 13 (Patau syndrome). Endorsed for use among "high-risk" women by the National Society of Genetic Counselors (NSGC), NIPT can obviate the need for amniocentesis or chorionic villus sampling (CVS), both of which are invasive and pose a small risk to the expectant mother and/or fetus.
The comprehensive roll out of NIPT would result in testing for trisomies among a considerable number of the approximately 5 million American women who become pregnant each year, not just the much smaller sub-set of women who undergo amniocentesis or CVS. NIPT has the potential to be a harbinger of great change for genetic counselors, pregnant women, and people with disabilities, and undoubtedly will become caught in the political crossfire around abortion.
At this point, NSGC recommends that NIPT only be utilized for higher-risk pregnancies and accompanied by counseling from a certified genetic counselor. It does not endorse NIPT as a routine, first-tier test, and recommends follow up, depending on test results, with a conventional diagnostic procedure, typically amniocentesis. One of the few expert bodies to provide guidance on NIPT, the California Technology Assessment Forum, concurs with the NSGC, recommending that NIPT serve as an advanced prenatal test for trisomy 21 and trisomy 18 (but not trisomy 13 which demonstrated lower sensitivity rates in studies conducted to date).
Notwithstanding these measured recommendations, the history of prenatal testing in America suggests that NIPT's path to routinization as a first-tier technology is all but assured. When amniocentesis emerged on the reproductive health horizon in the 1960s, concerns about medical risks including miscarriage led to comprehensive clinical research on safety and efficacy. In 1976, after alarge-scale study commissioned by the National Institutes of Health's National Institute of Child Health and Development involving one dozen medical centers and over 2,000 women (subjects and controls), amniocentesis was declared safe. However, in order to balance the risk of miscarriage with the elevated chance of giving birth to a child with Down syndrome, the age of 35 was established as the threshold when these two reached parity, in fractional terms, 1/200. For decades this contingently determined category of "high-risk" (even as the denominator in the fraction increased to 500) was fixed in prenatal care, bolstered by rationales of institutional cost-savings, disease prevention, and improvement of the gene pool. Following the federal decriminalization of abortion in 1973, which made pregnancy termination a legal option for women, amniocentesis rates rose dramatically in America, from a few hundred performed in the late 1960s to over 200,000 procedures annually by the early 1990s.
Concomitant to rising rates of amniocentesis, new non-invasive prenatal tools, such as maternal serum alpha-fetoprotein screening (MSAFP) were developed and pregnancy, already medicalized, became geneticized. NIPT is the next step in this process, providing the conclusive results of an invasive diagnostic procedure with the ease of a blood draw.
Notably, the era of defining high-risk pregnancy according to maternal age is coming to a close, a shift that could spur the growth of NIPT. In 2007, the American College of Obstetricians and Gynecologists revised its guidelines to recommend that all women, regardless of age, receive prenatal screening, in large part because new non-invasive technologies such as ultrasound-based nuchal translucency (which assess risk of Down syndrome, other chromosomal anomalies, and some congenital heart problems) were rapidly being incorporated in prenatal care. For many, ACOG's revision represented the broadening of prenatal care options and greater reproductive autonomy for women of all ages and socio-economic backgrounds.
Yet this revision soon prompted outcries from the Down syndrome community, which perceived the expansion of prenatal screening as a threat to the existence, and future existence, of people with developmental and intellectual disabilities. In many cases, people with disabilities and parents of children with disabilities have had negative experiences with genetic testing and genetic counseling, and have expressed grave concerns about the discriminatory implications of universal screening for genetic conditions. Companies marketing NIPT emphasize that the genetic information captured by the test will help women make informed choices about pregnancy and parenting, yet their glossy publicity can be misleading. NIPT promotional materials tend to conflate trisomies 13, 18, and 21 even though the first two are rare conditions characterized by very limited lifespans, whereas people with Down syndrome usually lead long (the average lifespan is now 60) and productive lives with varying physical and cognitive limitations. Reacting to the NIPT website produced by Sequenom to market the MaterniT21plus prenatal test, one father of a child with Down syndrome balks, "for parents, advocates, and people with the condition, Down syndrome is not a mistake or a defect; it is a way of being human."
The prospect of expanded prenatal testing has also fueled the fire of anti-abortion and right-to-life activists who anticipate skyrocketing pregnancy termination rates. Thus, NIPT could easily become a flashpoint for legislation such as the Abortion Ban for Sex Selection and Genetic Abnormalities, recently introduced in the Missouri legislature, and just one of the 92 provisions restricting abortions enacted in 24 states in 2011.
If NIPT becomes part of routine prenatal care, and if eventually accepted as a first-tier test, it poses real challenges for genetic counselors, whose professional charge is to communicate genetic information to a wide range of clients in a manner that simultaneously respects reproductive autonomy and the rights of people with disabilities. At the same time, NIPT could portend the gradual obsolescence of the bread-and-butter practice -- prenatal screening and testing -- of genetic counselors, especially if this technology becomes routinely offered in primary care settings with no genetic counselors on staff to interpret test results.
The biotech companies at the forefront of developing NIPT, Verinata Health, Sequenom, and Ariosa, are eager to market these tests not just to genetic health professionals but also to ordinary Americans. Yet as the U.S. Government Accountability Office has found, direct-to-consumer genetic tests are insufficiently monitored and raise a host of unresolved ethical questions. Without proper mechanisms for the regulation of genetic technologies and tests, it is as yet unclear how NIPT will enter the medical and clinical marketplace and who, if anyone will facilitate personally meaningful decision-making for pregnant women.
Those of us committed to balancing reproductive justice, disability rights, and regulated biotechnological innovation should keep a close eye on NIPT's integration into prenatal and genetic health services.
Correction: A previous version of this post incorrectly stated that the father of a child with Down syndrome was reacting to Ariosa's Harmony™ prenatal test. He was actually referring to Sequenom's MaterniT21plus prenatal test. We regret the error.