There are two ways that chromosomal abnormalities can be detected during pregnancy – screening tests and diagnostic tests.
- Screening tests, like Sema4 Noninvasive Prenatal Select, can help you understand whether there is an increased risk that your baby has a certain chromosomal abnormality. Screening tests are available as early as 9 weeks into pregnancy and typically are noninvasive, meaning they should not pose any risk to your pregnancy. This type of test will not give you a definitive ‘yes’ or ‘no’ answer
- Diagnostic tests with amniocentesis or chorionic villus sampling (CVS) can detect whether your baby has a certain chromosomal abnormality. While these types of tests offer more definitive answers, they are invasive procedures that are also associated with a small risk of miscarriage
Because of the small risk associated with diagnostic tests, some women prefer to start with a screening test, such as Sema4 Noninvasive Prenatal Select. If the results of a screening test show an increased risk of a chromosomal abnormality, genetic counseling is recommended. Your healthcare provider may also recommend diagnostic testing to confirm the result. Not all women who screen positive will have an affected child.