Prenatal testing

Testing for birth defects

You get to choose whether to have prenatal testing for birth defects. These tests can give us information about your developing baby’s health, but they can’t detect all birth defects.

Screening tests can identify risk that your baby may be born with certain birth defects. These screenings are completely safe and pose no risk to your pregnancy.

A screening test may be right for you if:

• You want to know your baby’s risk for birth defects like Down syndrome or spina bifida
• You want more information before having a diagnostic procedure
• You’re OK with a test that might miss certain birth defects

Diagnostic procedures can accurately detect certain birth defects. These tests are considered safe, but they’re more invasive than other prenatal tests and there’s a small risk of miscarriage (less than 1 in 300). 

We’ll talk about all your options during your prenatal care appointments. We may recommend testing for birth defects based on your age, family history, or signs that there could be a problem. However, it’s your choice. If you’re wondering whether it’s the right choice for you, our prenatal testing decision guide can help you understand your options.

A diagnostic procedure may be right for you if:

• You want to know for certain whether your baby has a chromosome abnormality like Down syndrome
• You're willing to have a test that includes a very small risk of miscarriage (1 in 300)

Is testing for birth defects the right choice for you?

Choosing whether you’ll have these tests is a personal decision. Keep in mind that some tests vary by state — we’ll talk more about them at your prenatal care appointments and answer any questions you might have.

4 types of screening tests

Serum Integrated Screening
Testing starts in the first trimester.

• There’s no increased risk for miscarriage.
• Final results are available in the second trimester. No first trimester results are available.

Sequential Integrated Screening
Testing starts in the first trimester.

• There’s no increased risk for miscarriage.
• Slightly higher detection rate for certain types of birth defects; may provide early detection of others.
• Preliminary positive and negative results are provided in the first trimester. Final results are available in the second trimester.

Non-Invasive prenatal screening (NIPT)
Testing at 10 to 24 weeks.

• No increased risk for miscarriage.
• Offered if you’re at a higher risk for having a baby with a chromosome problem. 
• Doesn’t require first trimester testing but does require additional testing to confirm a diagnosis.
  

Quad marker screening
Testing starts in the second trimester.

• There’s no increased risk for miscarriage.
• Doesn’t require first trimester testing. If you decide later in your pregnancy that you want to have a screening, this is an option for you.

2 types of diagnostic procedures

CVS (chorionic villus sampling)
Testing starts in the first trimester.

• Risk for miscarriage is less than 1 in 300.
• Detects more than 99% of chromosome abnormalities.
• Partial results are available right away. Complete results are available in the second trimester after additional tests.

Amniocentesis
Testing in the second trimester only.

• Risk for miscarriage is between 1 in 300 and 1 in 500.
• Detects more than 99% of chromosome abnormalities.
• All results are available at the same time.
• Follow-up testing is rarely needed.