The reporting of results varies depending on the lab. Results might be reported as positive or negative, as high risk or low risk for an abnormality, or as a probability.

Results follow-up:

  • Chromosomal conditions. If the test results are normal, you might not need further testing. However, if results indicate an increased risk that the fetus has a chromosomal abnormality, amniocentesis or CVS will be offered. Further testing using the sample from amniocentesis or CVS can be used to confirm the diagnosis.
  • Rh factor. If you're Rh negative and the test results indicate that the fetus is Rh negative, you won't need medication to prevent your body from producing Rh antibodies during your pregnancy. If the test results indicate that the fetus is Rh positive and you've previously become sensitized, your baby will be carefully monitored.

Chromosomal abnormalities can't be corrected. If your baby is diagnosed with a chromosomal abnormality, you'll need to decide whether to continue with your pregnancy or what steps to take to care for your baby during pregnancy and after he or she is born. Your health care provider or a genetic counselor can help answer any questions you might have.

Regardless of the results of prenatal cell-free DNA screening, if you have risk factors that suggest your baby might be at increased risk of a chromosomal or genetic condition, you have the option of undergoing amniocentesis or CVS.

July 29, 2017
  1. AskMayoExpert. Prenatal cell-free DNA screening. Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2016.
  2. American College of Obstetricians and Gynecologists Committee on Genetics and the Society for Maternal-Fetal Medicine. Committee Opinion No. 640: Cell-free DNA screening for fetal aneuploidy. Obstetrics & Gynecology. 2015;126:e31.
  3. Allyse M, et al. Non-invasive prenatal testing: A review of international implementation and challenges. International Journal of Women's Health. 2015;7:113.
  4. Society for Maternal-Fetal Medicine Publications Committee. #36: Prenatal aneuploidy screening using cell-free DNA. American Journal of Obstetrics and Gynecology. 2015;212:711.
  5. Prenatal cell-free DNA screening. National Society of Genetic Counselors. Accessed Jan. 18, 2017.
  6. Palomaki GE, et al. Prenatal screening for common aneuploidies using cell-free DNA. Accessed Jan. 17, 2017.
  7. Gregg AR, et al. Noninvasive prenatal screening for fetal aneuploidy, 2016 update: A position statement of the American College of Medical Genetics and Genomics. Genetics in Medicine. 2016;18:1056.