Health & Pregnancy

What are birth defects tests?

Birth defects tests are done during pregnancy to look for possible problems with the baby (fetus). Birth defects develop when something is wrong with genes or chromosomes, an organ, or body chemistry. A birth defect may have only a mild impact on a child's life, or it can have a major effect on quality of life or life span.

Birth defects include:

• Genetic disorders, such as Down syndrome and trisomy 18.
• Diseases passed in a family, such as Tay-Sachs, sickle cell anemia, and cystic fibrosis.
• Structural problems, such as heart defects and neural tube defects, including spina bifida.

What are the types of tests?

There are two types of birth defects tests: screening and diagnostic.

• Screening tests show the chance that a baby has a certain birth defect. It can't tell you for sure that your baby has a problem. If the test result is "positive," it means that your baby is more likely to have that birth defect. So your doctor may want you to have a diagnostic test to make sure. If the screening test result is "negative," it means that your baby probably doesn't have that birth defect. But it doesn't guarantee that you will have a normal pregnancy or baby.
• Diagnostic tests show if a baby has a certain birth defect.