Chorionic Villus Sampling.

I've heard about a test called chorionic villus sampling. What is it?
Chorionic villus sampling (CVS) is done to detect genetic abnormalities. Sampling is done early in pregnancy, usually between the 9th and 11th weeks.

How is the test done?
Ultrasound is used to locate the fetus and the placenta. A small piece of tissue is removed from the placental area with an instrument placed through the cervix or with a needle inserted through the abdomen.

Are there risks in having CVS done?
There is a small risk of miscarriage with this procedure. Only someone with experience should perform this test.

Why is this test ordered?
The advantage of CVS is an earlier diagnosis than amniocentesis, if a problem exists. The test can determine various fetal problems, such as Down syndrome, Tay-Sachs disease and cystic fibrosis. Some women choose to have this test because they want results earlier so they can make decisions about the pregnancy.

Is CVS better than amniocentesis?
CVS can be done much earlier in pregnancy, and results are available in about a week. If the woman decides to terminate the pregnancy after learning results of the test, the procedure can be performed earlier in pregnancy and may carry fewer risks. On the other hand, the risk of disturbing a normal pregnancy is slightly higher with CVS than with amniocentesis.

Should I have this test done?
Each woman's pregnancy is different. Discuss this test with your doctor, who will help you determine if your particular case requires it.