Genetic Testing for Birth: What Expecting Parents Need to Know
An expecting parent's guide to genetic testing, counseling, and what to do with all that data.
Genetic testing is now a commonplace part of a pregnancy. Testing for inherited diseases that can be unknowingly passed on to your offspring is a standard practice, ordered by doctors as part of the routine prenatal checklist, and usually covered by insurance.
Autosomal recessive inherited disorders, another name for passed down genetic illnesses, are something that doctors seek out so that expectant parents can decide if the information changes their willingness (or ability) to bring their baby into the world. Also, having the information in advance that, say, the baby has a 25 percent chance of developing Cystic fibrosis, allows doctors to test for it as part of the baby’s newborn screening, and closely monitor it in the first few months of life, even before symptoms arise. With Cystic fibrosis, early identification and treatment is key to controlling many of the symptoms, enabling children to live longer, healthier lives.
Most facilities also provide genetic counseling to help parents interpret their test results, both the mathematics of probability (like the fact there’s a 1 in 4 chance that a baby whose parents are carriers of Cystic fibrosis will be affected by the disease) and beyond. “What parents do in those situations is a very personal choice” says Dr. Ira Jaffe, OB/GYN at Rosh Maternal & Fetal Medicine in New York City. “We arm them with the information they need.”
Genetic Ancestry and Technology
In the past, expecting parents were offered this type of testing based on ancestry. Eastern European Jews, for example, face an increased risk of the nervous system disorders Tay-Sachs Disease and Canavan disease, as well as familial dysautonomia. People of African ancestry and Mediterranean descent have a higher risk of Sickle cell disease. Celts and Nords run a greater risk cystic fibrosis. Or for those unsure of their ancestry, doctors could order a panel test that looked for only the most common autosomal recessive inherited disorders. Jaffe says that technology has improved so much today that laboratories can now test for a much wider range of such diseases, at minimal extra cost, meaning most facilities now provide what’s called a universal panel, for everyone.
Another type of testing that’s typically called genetic testing is chromosomal screening. While it’s technically correct to call chromosomal screening a genetic test, since all genetic material is contained in chromosomes, Dr. Jaffe recommends sticking to the term chromosomal, to avoid confusion. Chromosomal testing is the standard blood test that expectant mothers do at 10 weeks to check for the presence of extra chromosomes, and therefore the potential risk of conditions including Down syndrome. Based on the results, or if the mother is 35 or older, expecting parents may opt for additional tests done on the fetus itself.
What to Do with the Genetic Test Answers
Expectant parents put a lot of emphasis on chromosomal and genetic test results, and rightfully so. But Dr. Jaffe says the most critical conversation may be the one that happens before the tests are administered. “You should think of a medical test, any medical test, whether it’s a maternal blood test or a biopsy, as you’re asking a question,” he says. “It’s a question. Don’t assume that you’re going to get the answer you want.” He stresses the importance of thinking about the potential answers beforehand, and having a candid conversation with your partner. That way, the question, as well as its answer, becomes more actionable, and ultimately less stressful.