Birth defect testing is done during pregnancy . It looks for possible problems with the fetus. Birth defects results when something is wrong with the gene or chromosome, an organ or body chemistry.  A birth defect can be mild and not have a huge impact on the child’s life. It can also be  severe and have a huge impact on the child’s life.

Birth defects include the following :

• genetic defects such as Down’s syndrome and trisomy 18
• diseases passed down from the family which includes Tay Sachs, sickle cell anemia  and cystic fibrosis
• structural problems such as  heart defects and neural tube defects such as spina bifida.

What are the different types of birth defects tests.

The are two types  of tests  for birth defects.  These are screening and diagnostic tests.

Screening tests : They  show the chance that a baby has a birth defect.  These tests can tell you for sure. If the results are positive, it means that your baby has a chance of having a birth defect and your doctor may want to give you a diagnostic test. If the results are negative, it means the baby doesn’t probably have a birth defect. However that doesn’t mean that you will have a normal pregnancy or healthy baby.

Diagnostic tests : This test shows if a baby has a certain type of birth defect.

Screening tests for birth defects involves blood tests and ultrasounds. You may want to have tests to know if there is a problem so you can work with a doctor and hospital to care for your baby after birth. The blood test looks for the amount of certain substances in the blood. The doctor uses an ultrasound to look for certain changes in the baby.

The diagnostic test involves taking some of the baby’s cells and looking at the genes and chromosomes.

However no test is 100% accurate.  A test may be negative even if the child has a birth defect . You can also have a false positive  which means the child does not have a birth defect but the result comes out positive.

You may have only a first trimester test or a second trimester test. You can also have an integrated test which combines the results of tests you have in the first and second trimesters.

Who needs a birth defect test ?

Pregnant women and their spouses   can choose whether to have this test or not. Some women decide not to have this test because they will continue with the pregnancy regardless of the results

If you decide to have the test, you may want to talk to  a genetic counsellor who will advise you on reasons to have or not have the test and give you the support and resources you need.

It can be very emotional on deciding whether you want to have the test or not. You have to think about how the result will mean to you and affected your pregnancy choices .