As an Ashkenazi Jew planning to have a baby, I sure as heck wanted carrier screening for Tay-Sachs disease. But that disease is incurable and lethal. What about diseases that don’t severely limit lifespan and aren’t that disabling? During my pregnancy, I went on to have amniocentesis, which included testing for Down syndrome and – because of my family history — for a few genes associated with autism and mental retardation. But even as I was tested, I had no idea what I’d do if results came back positive.
Sometime soon, almost every expectant family may be faced with such life-and-death decisions. New tests are arriving that can detect Down syndrome by analyzing fetal DNA in the mother’s blood during the first trimester of pregnancy. Without the risks of amniocentesis and chorionic villus sampling, this technology lowers the bar for testing, maybe even allowing it to be offered to younger women. Blood tests for other disorders are sure to follow: Last month, two studies demonstrated that thousands of fetal genes can be analyzed from a small blood draw from the mother.
In a heavily-tweeted, subscription-only essay, Hank Greeley at Stanford Law School’s Center for Law and the Biosciences warned that we need to prepare for the ethical, legal and practical effects of being able to readily sequence fetal genomes. If these tests become cheap enough to offer routinely, will mothers feel pressured to have them? How will families decide whether a child’s life is worth living? Will researchers keep trying to improve treatment options, and will anyone fund their work? Are we headed for a society where all kids aren’t just above average, but genetically pristine?
In a post on our sister blog, Thrive, Brian Skotko, a clinical genetics fellow in Children’s Down Syndrome program, asks, “Will babies with Down syndrome slowly disappear?” Actually, they already are disappearing, even with our clunky 20th century technology. Research reviewed by Skotko in 2009 showed a 15 percent decrease in U.S. births of babies with Down syndrome between 1989 and 2005 – instead of the 34 percent increase that would have been expected with women waiting longer to have children.
But who’s to say a child with Down syndrome shouldn’t be given a chance at life? Just read the comments on Skotko’s post from parents who are among the reported 8 percent of families choosing to carry on with their pregnancy. “Things have never been more promising for people with Trisomy 21,” one wrote. “Educational, social and medical advances have improved their lives immeasurably in recent decades, and I would love an opportunity to share this with medical students.”
Take cystic fibrosis. Because of advances in care, U.S. infants born with CF have a dramatically increased life expectancy – 37.4 years in 2008, versus a median of 6 months in 1959. Nonetheless, a Massachusetts study led by the New England Newborn Screening Program and Children’s Hospital Boston found that the number of live-born infants with CF dropped by about half between 1999-2002 (before widespread use of prenatal carrier screening) and 2003-2006. (This decline doesn’t necessarily reflect pregnancy terminations, since carrier couples have other options — donor eggs or sperm, pre-implantation genetic diagnosis, or not conceiving at all.) Notably, those babies born with CF tended to have mutations associated with less-severe disease, suggesting that families considered quality of life in making their reproductive decisions.
Sickle cell disease presents a tougher dilemma, since identifying the genetic mutation in a fetus doesn’t necessarily predict disease severity. Some children have a relatively benign course; others live a life of pain and suffering. (Newer genetic discoveries could lead to better prediction.) In a large U.S. study in 1994, half of the women with a positive fetal diagnosis chose to terminate their pregnancy, and 64 percent did so when the diagnosis was made before the 20th week of gestation.
So using genetic information to make reproductive decisions isn’t new. But if simple, safe fetal gene tests become routine in prenatal care, will society deal kindly with children born with genetic conditions, even mild ones?
As early as 1983, a government report warned that couples refusing testing, or choosing not to terminate an affected pregnancy, might be blamed or stigmatized for making an “irresponsible choice.” A 1991 report from the AMA even cited an insurance company that tried to deny health care coverage to a baby with CF, arguing that since CF had been diagnosed prenatally, it constituted a preexisting condition.
In the early 1970s, sickle-cell carrier screening was forced upon African Americans in many states, with little accompanying education, often without confidentiality, and sometimes resulting in insurance and employment discrimination. All this before a fetal test was even available.
Will the ease of the new fetal gene tests finally usher in an era of eugenics? I have enough faith in the medical community to doubt this will happen. But it would pay to take a second look at this 20th century history before putting 21st century technology into practice.