What is Prenatal Cell-Free DNA Screening?
Prenatal cell-free DNA screening, also known as non-invasive prenatal screening (NIPS), is a laboratory test that uses a pregnant woman's blood to assess the risk of her developing baby having certain chromosomal conditions, including trisomy 21 (Down syndrome), trisomy 18 (Edward syndrome), and trisomy 13 (Patau syndrome).
Why Is Prenatal Cell-Free DNA Screening Important?
A prenatal cell-free DNA screening test can provide additional information about the health of a developing baby earlier than is possible with other prenatal tests, like an amniocentesis. The earlier the information is available, the more time a pregnant woman and her doctor have to develop a plan of care.
Preparation for Prenatal Cell-Free DNA Screening
No preparation is necessary for a prenatal cell-free DNA screening test. All that is needed is a sample of the pregnant woman's blood.
Procedure for Prenatal Cell-Free DNA Screening
A health care provider takes a sample of the pregnant woman's blood and sends it to a laboratory to be tested for cell-free DNA. The laboratory test looks for pieces of the baby's DNA that have been separated from the mother's DNA and are now free-floating in her bloodstream. These pieces of the baby's DNA can help to assess the risk of the baby having certain chromosomal conditions.
Types of Prenatal Cell-Free DNA Screenings
There are two types of prenatal cell-free DNA screening tests available:
- Non-invasive prenatal screening (NIPS): This type of screening looks for pieces of the baby's DNA in the mother's blood. It is available during the first trimester (up to 20 weeks gestation) and is used to screen for certain chromosomal conditions such as Trisomy 21 (Down syndrome), Trisomy 18 (Edward syndrome) and Trisomy 13 (Patau syndrome).
- Non-invasive prenatal testing (NIPT): This type of testing looks for more than just pieces of the baby's DNA in the mother's blood. It is available in the second trimester (20-40 weeks gestation) and is used to screen for a variety of chromosomal conditions, such as inherited gene disorders (e.g. cystic fibrosis) and gender.
Risks of Prenatal Cell-Free DNA Screening
A prenatal cell-free DNA screening test is a very low-risk procedure with few, if any, risks. The only risk is a false positive result, which indicates an abnormal result when there is truly no abnormality.
When Should a Prenatal Cell-Free DNA Screening Be Done?
A prenatal cell-free DNA screening can be done any time during the pregnancy, but it is typically offered during the first trimester (up to 20 weeks gestation) or the second trimester (20-40 weeks gestation). A healthcare provider or patient can decide which trimester is best for screening, based on individual circumstances.
Conclusion
Prenatal cell-free DNA screening is a laboratory test that uses a pregnant woman's blood to assess the risk of her developing baby having certain chromosomal conditions, including trisomy 21 (Down syndrome), trisomy 18 (Edward syndrome), and trisomy 13 (Patau syndrome). The test is a very low-risk procedure with few risks, and no preparation is necessary for it. It can be done any time during the pregnancy, and is typically offered during the first or second trimester.