Because Down’s Syndrome screening is not practical to perform for every pregnancy, and because of the small amount of risk to the fetus, this testing is not commonly done. There are simple screening tests that can help identify pregnancies with a high risk for Down’s Syndrome. If one of these tests indicates a propensity for Down’s Syndrome, additional testing can be done.

What Is Down Syndrome?
Down Syndrome babies have three copies of the 21^st chromosome instead of the normal two copies. The additional genetic material changes development, causing low muscle tone, a small stature, an upward slant to the eyes and a single crease across the center of the palm. Down Syndrome may also cause cognitive disabilities, and some babies born with this condition may have severe mental impairment. Not all people with Down Syndrome show all of the characteristics. Some people may show all or some of the characteristics, but the characteristics may not be pronounced.

There is no treatment for Down Syndrome that will eliminate or cure the condition. Babies born with Down Syndrome will be assessed shortly after birth for illnesses that could be life threatening, and during the early years to measure cognitive development.

Screening
Screening differs from a test in that a test gives a positive answer. Screening estimates the risk that the patient may have the disease. Screening has more instances of false positives or false negatives, but can show if a patient should actually be tested or not.

In maternal serum screening, the mother’s blood is checked for markers. The markers are a combination of alpha-fetoprotein, unconjugated estriol and human chorionic gonadotropin. This is known as the Triple Test. Depending on circumstances, the inhibin A marker is tested. When this marker is added, the test is known as a Quadruple Test. These tests are done in the 15^th to 18^th week of pregnancy. The results, along with the mother’s age, determine if there is a higher risk for having a Down Syndrome baby.

Another marker, PAPP-A, was recently found, and this can be tested even earlier than the 15^th week. PAPP-A (pregnancy-associated plasma protein A) is produced by the covering of a newly fertilized egg. If the levels of this protein are low in the first trimester, there is a chance that the fetus could have Down Syndrome.

If screening indicates an elevated risk of Down Syndrome, talk to your doctor about what this means. Remember that screening only indicates risk and isn't a guarantee that your child will have the condition. It also offers no indication of the severity of Down Syndrome symptoms that will appear when your child is born.