While we are unable to test for all types of congenital (inherited), developmental and medical problems that can affect children, you can have testing done to see if you are at increased risk of some abnormalities.
The Sequential ScreenSM test is used to screen for Down syndrome (Trisomy 21), Edward Syndrome (Trisomy 18) and spinal abnormalities (such as spina bifida). To perform this test, you will have an ultrasound between 11-13 weeks in the pregnancy to measure how thick the skin is on the back of the baby’s neck (the nuchal translucency). You will have blood drawn the same day as the ultrasound (to complete step 1 of the screen) and additional blood work drawn 2-3 weeks later (to complete step 2). This test is 80-90% accurate for detecting these 3 abnormalities. This is a noninvasive test with no risk to the pregnancy and is offered to all pregnant patients.
Amniocentesis and chorionic villus sampling are invasive tests usually offered to women over age 35 or women found to be at high risk of problems based on the sequential screening test, but any woman can ask for these tests. They are up to 99 percent accurate for diagnosing chromosomal abnormalities. Since they are invasive, there is a risk of miscarriage associated with them. With amniocentesis there is about a 1/200 to 1/400 risk of miscarriage and with CVS it is slightly higher at 1%.