Four million American women are expecting a child this year, and many of them will encounter something entirely new in human pregnancy. Based on a simple blood draw at an initial prenatal visit, they'll be able to learn key genetic information about the fetus they're carrying—and face potentially wrenching decisions about what to do.
These noninvasive prenatal tests, called NIPTs, work by using a sample of cell-free fetal DNA circulating in the mother's blood to detect chromosomal conditions. The tests' most frequent target is trisomy 21, the genetic variation that causes Down syndrome in approximately one in every 700 births in the U.S.
Bioethicists, genetic counselors and advocates for disability rights have nervously anticipated the commercial rollout of these tests. Even—or perhaps especially—those who firmly support reproductive rights know that NIPTs have profound implications.
The tests have the potential to transform women's experience of early pregnancy, reduce the number of people with Down syndrome, and reinforce the assumption that Down syndrome is a dread disease to be prevented. Ultimately, these tests could dramatically reshape our understanding of what it means to be healthy and normal.
Since the end of 2011, four U.S. companies have launched slightly different versions of NIPTs (as well as a bevy of patent-infringement lawsuits against each other). As a commercial product, NIPTs are in a rare and sought-after category: the kind whose introduction creates a new demand and a large new consumer base. Because the predominant diagnostic prenatal test, amniocentesis, is invasive and carries some risk, only about 2% of pregnant women in the U.S. undergo it, roughly 100,000 per year. NIPTs could push that number into the millions in the next few years.
One of the most visible NIPTs on the market is Sequenom's MaterniT21 PLUS, a name that conflates motherhood and the trisomy 21 link to Down syndrome. In 2012, Sequenom alone processed 120,000 tests. The company has just announced that it is expanding its testing capacity to more than 300,000 samples per year.
Ideally, genetic counselors or medical professionals would work with expectant parents before they decide to take a test like MaterniT21 PLUS, giving them objective information and helping them to fully understand what could lie ahead. Because the tests are performed so early in pregnancy, NIPTs theoretically give parents more time to meet with parents who have a child with Down syndrome, and to gain balanced information about the joys and challenges of raising a child with the condition before deciding whether or not to abort.
The problem is that the surge in the number of women taking these tests is swamping the available counseling resources. The National Society of Genetic Counselors estimates that there are only about 3,000 certified genetic counselors practicing in the U.S. Many parents will wind up taking their cues from the glossy brochures of the NIPT companies, with their language about "risk" and "abnormalities" and their images of perfect babies with no visible disabilities. Meaningful and responsible genetic counseling is supposed to be non-directive, marketing is intended to persuade.
Several flagship medical organizations that represent obstetricians, genetic counselors and medical geneticists—including the American Congress of Obstetricians and Gynecologists and the National Society of Genetic Counselors—have issued statements urging caution. All recommend that NIPTs be reserved for high-risk pregnancies and not used as part of routine prenatal care. And the groups concur that counseling by trained genetic-health professionals should accompany testing.
A recent statement by the American College of Medical Genetics and Genomics does a particularly good job of providing accurate and useful information for potential parents of children with Down syndrome. But the advice of these medical professionals and genetic counselors is up against a growing commercial force.
Beyond the immediate questions raised by the existing NIPTs looms an even more unsettling prospect: the development of whole-genome fetal tests that can deliver far more extensive information about a child's genetic makeup and predispositions. As with the gene tests currently available, most of the results will be presented as risk probabilities about conditions for which few, if any, therapies are available. What will parents do, for example, if they discover that their 10-week-old fetus has a five times higher-than-average chance of being diagnosed with breast cancer later in life, or a 34% higher-than-average risk of developing Alzheimer's 70 years from now?
Like so many other powerful technologies, fetal gene tests must be used with caution and care. Exactly what that entails is a concern not simply for medical professionals, or for people with Down syndrome and their advocates, or for companies marketing NIPTs. This portentous development in prenatal testing also raises thorny ethical problems for parents-to-be—and for everyone who cares about how we collectively understand what it means to be "healthy" and who counts as "normal."
Ms. Darnovsky is the executive director of the Center for Genetics and Society in Berkeley, Calif. Ms. Stern is a medical historian at the University of Michigan and the author of "Telling Genes: The Story of Genetic Counseling in America" (Johns Hopkins, 2012).
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