UAB Medicine

High Risk Pregnancy - Prenatal Genetic Testing

All pregnant women have a 2-4% chance of having a baby with a  birth defect . Although most birth defects cannot be diagnosed before the baby is born, three relatively common birth defects can be diagnosed prenatally.

One is a group of abnormalities called   neural tube defects  (problems with formation of the brain or spine, such as spina bifida) and the other two are chromosome abnormalities called Down syndrome (Trisomy 21) and Edwards syndrome (Trisomy 18) . In most cases there is no family history of these defects, so any woman can have a baby with these problems.

Detection of these birth defects begins with a screening test that determines whether or not you are at increased risk of having a baby with these abnormalities. If your test is negative, it provides reassurance that your child is not affected. If your test shows you are at increased risk, you can then consider having a diagnostic procedure, such as amniocentesis or chorionic villus sampling (CVS) , performed for definitive diagnosis.