What Will Be the Consequences of the Latest Prenatal-Testing Technologies?
Here’s some big — and good — news on the birth-technology front, from Amy Dockser Marcus in the Wall Street Journal:
New, noninvasive blood tests are being developed for expectant mothers to find out if their babies have genetic conditions such as Down syndrome, without the risks of tests available now.
Pregnant women often opt for a prenatal test called amniocentesis that requires a needle to be inserted through the walls of the abdomen and uterus to draw a sample of the fluid surrounding the fetus. The test is uncomfortable and carries a small risk of miscarriage, as does another invasive test for genetic disorders called chorionic villus sampling, or CVS, that samples tissue from the placenta.
Now, scientists say new tests of fetal DNA sampled from a mother’s blood can be used to screen for Down syndrome, which occurs in one in 691 live births and causes cognitive disabilities. The new blood tests could be performed as early as nine weeks into a pregnancy—earlier than amniocentesis—and may be available as soon as the end of this year.
Other interesting bits:
The current crop of noninvasive tests grew out of a discovery made in the late 1990s by Dr. [Dennis] Lo at the Chinese University of Hong Kong. He found a fetus releases its DNA into the plasma of the mother during pregnancy, though within two hours of giving birth, the baby’s DNA vanishes.
Stanford’s Dr. [Stephen] Quake said he started thinking about the need for noninvasive tests when his wife was pregnant with their first child. His wife was over 35 years old and her doctors recommended amniocentesis.
As with most new birth technologies, I assume that less-invasive, earlier-acting (and, eventually, cheaper) birth technologies will produce their own set of unforeseen consequences. See Mara Hvistendahl‘s excellent book Unnatural Selection about the consequences of ultrasound machines and sex-selective abortion. Or consider this bizarre story from SuperFreakonomics:
It used to be that when a baby presented itself awkwardly, there was a good chance it would get stuck in the birth canal and endanger both mother and child. The forceps, a simple set of metal tongs, allowed a doctor or midwife to get a firm hold on the baby and adroitly pluck it out, like a roast suckling pig from the oven.
As effective as it was, the forceps did not save as many lives as it should have. It is thought to have been invented in the early seventeenth century by a London obstetrician named Peter Chamberlen. The forceps worked so well that Chamberlen kept it a secret, sharing it only with sons and grandsons who continued in the family business. It wasn’t until the mid– eighteenth century that the forceps passed into general use.
What was the cost of this technological hoarding? According to the surgeon and author Atul Gawande, “it had to have been millions of lives lost.”
I do wonder about the ramifications of ever-better prenatal testing. There will of course be ethical dilemmas on a family level, and perhaps on a societal level; but I also wonder how, if fewer children with various handicaps are born, our view of handicapped children and even adults may change. Your thoughts?