Prenatal Testing

Most babies are born healthy, but all pregnant women have a 3-percent to 5-percent chance of having a baby with a birth defect. At Swedish’s Maternal and Fetal Specialty Center we offer prenatal testing to detect these problems. Your test results can reassure you that your baby is healthy, help you prepare for a baby with special needs, or alert you if a serious problem is detected.

Types of tests available

During your pregnancy, you can choose a prenatal screening test and/or a diagnostic test. Screening tests determine the risks for certain fetal conditions. Diagnostic tests are used to confirm or diagnose the specific presence of certain fetal conditions.

Prenatal Screening

A prenatal screening test shows the risk for certain fetal conditions in pregnancy, but cannot actually diagnose them. The conditions screened include Down syndrome, Trisomy 18 (a serious chromosome condition), and spina bifida. Information from screening tests is used to determine whether a diagnostic test, such as amniocentesis, is advised..

We offer several prenatal screening tests at the Maternal and Fetal Specialty Center. Each screening test requires a blood draw. Some also use a nuchal translucency (NT) ultrasound to measure the fluid at the back of the baby's neck. Screening tests do not increase the risk for miscarriage. Only one prenatal screening test is done during a pregnancy.

What if my prenatal screening test is positive?

Remember: A screening test only estimates the chance for a certain problem. A "positive screen" does not mean there is definitely a problem with the baby. If your screening test is positive, you can to talk to a genetic counselor about the results. A genetic counselor can help you understand the results, and work with you to decide if you should have a prenatal diagnostic test.

Diagnostic tests

A prenatal diagnostic test is used to diagnose certain birth defects, such as Down syndrome, during pregnancy. Diagnostic tests are offered to women who have a positive prenatal screening test, are over 35 years of age, have had a previous pregnancy child with a birth defect, or a family history of a genetic condition. Prenatal diagnostic tests involve a small risk of miscarriage. Chorionic villus sampling (CVS) and amniocentesis are two of the more common diagnostic tests offered in our clinic.

Depending on your condition or screening results, you may have additional tests performed. Additional prenatal diagnostic tests might include a fetal echocardiogram, a nonstress test, or ultrasound.