First trimester screening

First Trimester Screening is a series of tests to see if you are at increased risk of having a baby with a chromosome anomaly such as Down Syndrome, Trisomy 13, or Trisomy 18. The following information is to help you decide if that testing is something you would like to do.

What are Down Syndrome, Trisomy 13, and Trisomy 18?

These are all genetic disorders where babies are born with too many chromosomes, which cause mental retardation and birth defects. Babies with Down Syndrome have an extra chromosome 21, which results in mental retardation and problems in the formation of the heart and digestive tract. Many babies with Down Syndrome are able to live an almost normal life, although they need extra help with learning and may have health problems. Babies with Trisomy 13 and 18 have very severe birth defects and almost never survive more than 2 years of life, and many of them die before they are born.

Who can have a baby with these conditions?

Anyone can have a baby with these conditions, but the chances increase as the mother gets older. Women over age 35 at the time their baby is due may be offered different testing because of this increasing risk.

What can this testing tell me?

The test can only tell you if you have an increased risk of having a baby with one of these conditions. Additional testing is required to confirm the diagnosis.

Why should I have a test to find out if I am at risk of having a baby with these conditions?

The testing is optional. Some people would want to know if they might have a baby with these conditions so they can be prepared for the extra work that is required to care for these children. Other people may choose not to continue a pregnancy affected with one of these conditions. Some people may decide not to have the testing because they would not change anything about how they would handle their pregnancy.

How is the testing performed?

The testing is done between 10 and 13+6 weeks of gestation. There are two parts to the test, an ultrasound to look at the fluid collection in back of the baby's neck (nuchal translucency or NT) and a blood collection from the mother. Together, the results of these tests give a number that describes your risk.

What happens if my test is positive?

If the test is positive, it means there is an increased risk for Down Syndrome, Trisomy 13, or Trisomy 18. You will have the choice to have another test done to confirm the diagnosis. The testing involves taking a sample of fluid from around the baby, or a sample of the placenta, which allows a way to count the chromosomes directly.

If my test is negative, will my baby definitely be normal?

The test is specific for the three conditions listed. As with any test, there is a chance that the result is a "false negative", or that the results are wrong. This chance is very small, but not zero. There are also lots of other problems that can occur during a pregnancy. Another ultrasound will be done around 20 weeks to check on how the baby is developing.

What if I am too far along to have First Trimester Screening?

There is a blood test that can be done in the second trimester, called a Triple test. Please let us know if you would like to do this test instead. It is not recommended that you do both first and second trimester screening, unless it is part of the same test (called "Sequential Screening").

Will my insurance company pay for this test?

You should contact your insurance company directly and ask if they cover the test.