The evolution of fetal screening

Once upon a time, everything about your baby was a surprise until the moment of birth. Is it a boy or a girl? Does he (or she!) have all 10 fingers and 10 toes? And, most important: is the baby healthy? Genetic disorders—Down Syndrome, Trisomy 18 and others—were often a surprise in the delivery room.

However, the new prenatal screening tests are a game changer. They represent a significant technological breakthrough because the key to identifying problems or genetic risks is being able to see the baby’s DNA. Amniocentesis and CVS accomplish this with amniotic fluid or placental material, both of which contain fetal cells and, hence, fetal DNA. But that means going inside the womb—with a needle, typically—and actually taking some cells. And that’s what carries the risk.

Recently, the introduction of “cell-free fetal DNA testing” has altered the landscape of prenatal genetic testing further. You may have heard of these tests by their brand names: Harmony or MaterniT21, among others. The technology for each is broadly the same: they rely on a sample of maternal blood with no risk to the fetus, and they have accuracy rates approaching those of fetal diagnostic test like amniocentesis or Chorionic Villus Sampling (CVS), but without any risk to the fetus. In other words, these new tests provide the best of both worlds—and a recipe for moral fission.

Read the full article here.