Prenatal screening tests are able to provide information about the chances for a baby to have a specific abnormality, such as Down syndrome. A benefit of screening tests is that they provide a risk assessment without putting the pregnancy at any risk. These tests use a blood test and/or ultrasound examination to determine whether a baby is at risk for genetic chromosome abnormalities, or specific birth defects such as spina bifida.
It is important to remember that screening tests are not able to tell us with 100% certainty if a disorder is actually present; it can only tell us if there is an increased risk. For many people, this information can then be used to help make decisions about pursuing diagnostic testing.