The push for prenatal blood tests is driven by simple reasoning: to reduce the number of invasive procedures that cause fear in the mother and a small risk to the baby while also providing information about genetic conditions to help guide the pregnancy.
Last December, the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine released a committee opinion calling the new prenatal blood tests a technology with “tremendous potential as a screening tool” for abnormal numbers of chromosomes. The tests will allow many women with high-risk pregnancies to forgo the riskier tests, according to Dr. Diana Bianchi, executive director of the Mother Infant Research Institute at Tufts Medical Center.
Several companies are now conducting clinical trials to determine whether their screening tests could be used in the general population of pregnant women. They hope to demonstrate that the tests are more accurate than conventional screening used in women not at high risk. Conventional screening has a false positive rate of about 5 percent and also may indicate there is a low risk of a problem when a fetus does have a chromosomal syndrome.
Bianchi sees a further upside to the new tests, which can provide earlier diagnosis. The benefit, she says, is not just that women could make decisions about whether to continue pregnancies based on information about the fetus, but that the growing area of fetal medicine might have more time to intervene.
“You could conceivably have 30 weeks to treat a condition,” said Bianchi, who last week presented early data at the meeting of the Society for Gynecologic Investigation in Florida showing the effects of an antioxidant drug in mice with a form of Down syndrome. The drug was administered through the pregnant mother’s food and was continued until the offspring were 8 to 10 weeks old. Mice that received the treatment were less hyperactive and displayed more normal exploratory behavior. Bianchi’s hypothesis is that the drug may reduce oxidative stress that interferes with normal brain development.
But Dov Fox, a fellow at Georgetown University Law Center, said that the tests may lead to a subtle societal shift that often gets left out of the debate. Providing the information might create what feels like a turning point for many — compelling a decision to do something or not do something that could gradually shift what is normal.
“It also exerts social pressure on parents to terminate pregnancy for fear of criticism or reproach from people who regard the choice — their child with a disability — as negligent, or irresponsible,” Fox said. “This increasing willingness to prevent the birth of children with impairments or genetic abnormalities may, moreover, bring a tendency to exclude rather than accommodate people whose abilities fail to meet the demands” of the everyday world.
A test returns results in black and white terms — positive or negative, or a risk expressed as a set of numbers. It can’t convey what a whole life would feel like.
In July 2007, when Julia was born, her mother instantly recognized the physical features of Down; she had been reading about them for months. Julia had slightly upturned eyes. Trafford recalls she had low muscle tone — she was a little bit floppy.
But as Courtney looked down at the baby in her arms, she felt that all the books she’d read had given her only the vaguest hints of how her daughter’s life would unfold. The way she and Trafford would hold their breath through her open-heart surgery. The way they would worry about Julia as they tried to get her to gain an ounce. The way they would get to know their head-strong, social little girl who wiggles her feet when she is excited and clinks her red popsicle with everyone’s cup in a joyous toast after dinner. The way she would have to be painstakingly taught how to jump and walk and practically everything else — and how that struggle would make it all that much sweeter.
Now, the parents have watched as her younger brother, Oliver, 2, seemed to learn faster from Julia — and is now helping to accelerate her development. As he has learned to string words together into sentences, Julia makes more of an effort, too.
The Kanes say they are part of a club that no one would think they want to join, but that they would never want to leave.
There is something else Courtney vividly remembers from the first time she held her daughter.
In some ways, it is an emotion specific to having a child she knew would be slow to speak, might never get married, and might never live independently. But in other ways, it’s the same feeling all parents have.Continued...