What does prenatal genetic testing screen for?

Prenatal genetic screening tests of the pregnant woman’s blood and findings from ultrasound exams can screen the fetus for aneuploidy; defects of the brain and spine called neural tube defects (NTDs); and some defects of the abdomen, heart, and facial features. This FAQ focuses on these tests.

What are the 2 types of prenatal genetic tests?

There are two types of prenatal genetic tests: screening tests and diagnostic tests.

• Screening tests do not diagnose a birth defect, they only determine if a fetus is at high or low risk for a specific condition.
• Diagnostic tests can diagnose certain fetal conditions with a high degree of accuracy.

What does genetic testing test for?

Genetic testing is a type of medical test that identifies changes in genes, chromosomes, or proteins. The results of a genetic test can confirm or rule out a suspected genetic condition or help determine a person’s chance of developing or passing on a genetic disorder.

What are the 3 prenatal tests?

What prenatal tests are done in the first trimester?

• Carrier screening for genetic conditions.
• Cell-free fetal DNA testing (also called noninvasive prenatal screening or testing).
• Chorionic villus sampling (also called CVS).
• Early ultrasound (also called first-trimester ultrasound).

Which prenatal diagnostic method is safest?

Ultrasonography and blood tests are safe and sometimes help determine whether more invasive prenatal genetic tests (chorionic villus sampling, amniocentesis, and percutaneous umbilical blood sampling) are needed.

Is there a prenatal test at MSH Toronto?

MSH Toronto offers First Trimester Screening (FTS). Earlier screening results allow a woman with a positive screen to access genetic counselling and/or non-invasive prenatal testing (NIPT) as a secondary screen or diagnostic testing sooner in her pregnancy.

When to use maternal serum screening ( 2nd trimester )?

Maternal Serum Screening (2nd trimester) continues to be available for patients presenting to care at later gestations. If your patient receives a positive prenatal screening result and would like an appointment in the Prenatal Genetics Clinic at CHEO, you must refer her to the Genetics Clinic.

What happens if your MSH6 test results are positive?

Both of these results should be considered positive. Everyone has two copies of the MSH6 gene, which we randomly inherit from each of our parents. Mutations in one copy of the MSH6 gene can increase the chance for you to develop certain types of cancer in your lifetime.

Where to go for prenatal testing in Ontario?

If your patient receives a positive prenatal screening result and would like an appointment in the Prenatal Genetics Clinic at CHEO, you must refer her to the Genetics Clinic. For more information on prenatal screening in Ontario, please see Prenatal Screening Ontario.