Expecting moms have the option of genetic testing in the first trimester to screen for chromosomal disorders. All genetic testing is optional, and might be recommended by your doctor depending on your risk factors, such as maternal age. cfDNA testing has been found to be more accurate than the most common screening test, nuchal translucency screening, and less invasive than the two most common diagnostic tests, amniocentesis and chrorionic villus sampling (CVS). Amniocentesis and CVS also come with a small risk of miscarriage.
What is cfDNA?
cfDNA is a screening test that uses a blood sample from an expectant mother to analyze pieces of fetal DNA that have leaked into her blood stream from the placenta. Unlike amniocentesis and CVS, cfDNA is a screening test, not a diagnostic test, meaning it cannot tell 100% whether or not a fetus will have any specific chromosomal disorder. However, the American College of Obstetricians and Gynecologists (ACOG) believes this test can be expected to identify 98% of trisomy 21 (Down syndrome) cases. You can also opt to be screened for various other chromosomal disorders with this test.
You might have heard of cfDNA tests called by the private laboratories' brand names for the screening: Ariosa's Harmony, Natera's Panorama, Sequenom's MatrnitT21 Plus, and Verinata's verifi.