5 Myths About Prenatal Screening
Confused about prenatal screening? Our expert explains the different types, when they’re used and what you need to know about the information they give you.
Pregnancy often comes with mixed emotions. For every moment of anticipation, there may be a moment of anxiety.
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For some women, anxiety rises with prenatal genetic screenings — tests that can help identify genetic abnormalities before a baby’s birth. Clinical geneticist Rocio Moran, MD, understands those fears. Part of alleviating them is separating myth from reality.
Certain tests — ultrasound and serum screening, for example — are available for all pregnant women. But some screenings are recommended only for high-risk pregnancies. If you are 35 or older, if you have had an abnormal ultrasound or blood screening, or if you have a family history of birth defects or genetic disorders, you may be high-risk.
You don’t have to figure it out on your own, though. “A genetic counselor is part of the medical team that helps individuals form testing strategies they are comfortable with,” Dr. Moran says. “It’s really based on each individual woman.”
Some prenatal tests — amniocentesis and chorionic villus sampling (also known as CVS) — are invasive and come with a risk of miscarriage. But thanks to newer noninvasive prenatal testing, many women won’t need those invasive tests at all.
“It’s a real improvement,” Dr. Moran says. “New technology finds abnormalities using only maternal blood.” Currently, the screening identifies pregnancies at risk for abnormalities only in certain chromosome numbers: trisomy 13, trisomy 18, trisomy 21 (Down syndrome) and sex chromosome disorders. If you want to learn more about whether this screening is right for you, consult a counselor.
“Labeling a child before birth is not the goal, but providing you and your medical team with as much information as possible is.”
Not all findings are as serious as trisomy 13 or trisomy 18. “We all carry variations in our genetic material. Some of those variations or genetic changes may only increase your risk of having a particular disorder,” Dr. Moran says. A counselor can help you understand what genetics can tell you — and what it can’t.
“Labeling a child before birth is not the goal,” she says, “but providing you and your medical team with as much information as possible is.”
Tests can find more abnormalities than ever before. But they can’t find everything. “Particularly in a high-risk situation, if a test comes back normal, it means that it is unlikely your child will have one of the disorders the test covers,” Dr. Moran says. However, it doesn’t rule out all abnormalities or genetic syndromes.
That is a tough message for a lot of parents. Counselors and geneticists are open and honest, but they also provide reassurance. Although genetic screenings can uncover frightening information, “the reality is that the majority of women go on to have healthy babies,” Dr. Moran says.
The information — even bad news — can help you manage your pregnancy. For example, if a test comes back positive for Down syndrome, your doctors can be prepared for a higher-risk pregnancy and help screen for associated conditions. Parents can then plan to deliver at a center that is prepared to care for a child with complex medical needs.
“We know this can be scary for women,” Dr. Moran says, “but we really want to empower them. Your genetic information can help you — and us — make more personalized medical decisions.”