Four years ago, when my sister-in-law was pregnant with her second baby at 36, I recall her telling me about how falling into the “35 and over category” meant she was now subject to genetic counseling and with that advised to get some sort of prenatal testing for genetic defects as a precaution. The first thing that popped into my head was the word “amniocentesis,” followed by an image of a giant needle probing my uterus (I was pregnant with my first at 31 years old back then, as well).
Back in the present: currently pregnant with baby No. 2 at 36 years old, it is my turn to listen to the kinds of prenatal-testing options available for me to undergo. And though I was always in the camp of “I’m having this baby no matter what happens,” and didn’t necessarily need or want to know if my baby was going to be born with genetic issues, my genetic counselor told me in very simple terms: getting tested also meant that when it was time to give birth, the medical team on-site would be that much more prepared if they knew that, say, a heart specialist or pediatric surgeon would need to be present during delivery having prior knowledge of my baby’s genetic condition or birth defects. With that, I made the decision to undergo genetic testing for my baby.
Bracing myself for getting tested, I was expecting to be given a detailed explanation of how one receives diagnostic genetic tests such as amniocentesis or chorionic villus sampling (CVS) – both invasive and involving a small risk of miscarriage (1 to less than 1 percent). However, during my genetic counseling session, I was told about the recent advancement NIPT (Non-Invasive Prenatal Testing) as a prenatal screening option to find out if a developing baby is at risk for Down syndrome and other genetic conditions. The best thing about NIPT (also called cell-free fetal DNA testing), is it involves a simple blood test – usually between 10-22 weeks – with zero risk of miscarriage. Apparently, science has found a way to test the miniscule amounts of a fetus’ cell-free DNA floating through mom’s bloodstream.
Hospitals and clinics across the board have started to offer NIPT to patients, including Dr. LeAnn Haddock, OB/GYN on the medical staff at Baylor University Medical Center at Dallas (Baylor Dallas). “Over the past year, we have been offering maternal screening for chromosomal abnormalities with a maternal blood draw in our office to evaluate cell-free fetal DNA. These tests are called Panorama, MaterniT21 and Harmony. These tests also screen for Down syndrome, Trisomy 13 and 18 and are able to determine fetal gender.”
Despite the “newness” of NIPT, expectant moms are already embracing the procedure in a big way. According to Haddock, “[It is] a very good alternative to accurately screen the fetus for Down syndrome (Trisomy 21), Trisomy 13 and 18. These are the most common types of genetic defects seen and of which can have long-term affects for newborn if not lethal.” She adds, “There is also screening available for certain genetic disorders, including Cystic Fibrosis, SMA and Fragile X. As these tests have become more available, cost-effective and limited to no risk to fetus, we have seen more than half of our patients desire the testing.”
So does this mean that the amnio and CVS are becoming obsolete? Certainly not. Haddock asserts that though these new tests boast higher sensitivity and accuracy, they are still not 100-percent accurate – there are still cases where further genetic evaluation is needed and invasive testing may provide clearer results. Still, NIPT is a very helpful gauge to determine your baby’s propensity toward a genetic condition and gives moms-to-be a less-risky option – a pre-prenatal test, if you will – before subjecting themselves to more invasive methods of prenatal testing.
Published March 2014
