Results

The reporting of results varies depending on the lab. Results might be reported as positive or negative, high risk or low risk for 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.
  • Fetal sex. If you're the carrier of an X-linked recessive disorder and the test results indicate that you're carrying a girl, you might not need further testing. If the test results indicate that you're carrying a boy, amniocentesis or CVS might be offered for further evaluation. In most situations, these tests can be used to diagnose a genetic disorder linked to the X-chromosome.
  • 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.

Feb. 23, 2016
References
  1. AskMayoExpert. Prenatal cell-free DNA screening. Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2015.
  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. Prenatal cell-free DNA screening: Q&A for healthcare providers. National Society of Genetic Counselors. http://nsgc.org/page/non-invasive-prenatal-testing-healthcare-providers. Accessed Jan. 6, 2016.
  5. Prenatal cell-free DNA screening. National Society of Genetic Counselors. http://www.acog.org/Resources-And-Publications/Endorsed-Documents. Accessed Jan. 6, 2016.
  6. Society for Maternal-Fetal Medicine Publications Committee. #36: Prenatal aneuploidy screening using cell-free DNA. American Journal of Obstetrics and Gynecology. 2015;212:711.

Prenatal cell-free DNA screening