Genetic Screening and Testing

Before you consider any testing, you should consider the question, “How will this information affect how I manage my pregnancy?” Your answer to that question will affect how you view these tests. Your choice of testing is personal.

If you do elect to undergo testing, you should understand the difference between a screening test, which gives a likelihood of there being an abnormality, versus a diagnostic test, which provides you with a definite diagnosis.

During your pregnancy, you will be given several options for genetic testing. Your choice of test depends on your individual desires and your risk of having a baby with a chromosomal abnormality. There are two general types of tests: screening tests and diagnostic test. Tests like the AFP4 and the First Trimester NT Screen are screening tests, which assess the likelihood of delivering a baby having Down’s Syndrome, as opposed to a diagnostic test, such as the CVS or amniocentesis, which will give a definite diagnosis (but also carries a small risk of miscarriage). The screening test can’t tell for certain that your baby is affected. However, it can help someone decide whether or not to have a diagnostic test. Down’s Syndrome represents most couples’ primary genetic concern because this is one of the most common chromosomal abnormalities that can survive to live birth. Every woman has a risk of giving birth to a baby with Down’s Syndrome and this risk increases with age. Your chance of having a baby with Down’s Syndrome at age 25 is 1/1,350, at age 30 is 1/900, at age 35 is 1/360 and at age 40 is 1/100. The majority of Down’s Syndrome children are born to women under the age of 35 because more babies are born to younger women. The tests below are available to determine your risk of having a child with abnormal chromosomes and particularly, Down’s Syndrome. You have the opportunity to choose the type of testing that meets your needs. You should consider the differences between a screening test that determines whether you have a pregnancy at greater risk for chromosomes of your child. The screening tests are risk-free to your pregnancy. The definitive tests do contain certain risks to your pregnancy. You should also consider how accurate (sensitive) the tests are and what you will do with the results. See the detailed description below for more information.