Chorionic Villus Sampling

Chorionic Villus Sampling (CVS) is a common prenatal diagnostic test used to assess the health of a baby before birth that has been available for more than 15 years. The procedure is usually performed when you are about three months pregnant, which is earlier than when an amniocentesis can be performed. It is performed by specialists in the Maternal-Fetal Medicine Center at Woman’s.

Procedure

Your doctor will use an ultrasound to determine the position of the placenta. Depending on its position, your doctor will choose one of two techniques: inserting a catheter (thin, hollow tube) through the vagina and cervix to the edge of the placenta, or inserting a thin needle through the abdomen to the placenta. In each case, a tissue sample is taken from the placenta.

This procedure takes only a few minutes. The placental tissue contains genetic material identical to that of the fetus, which is analyzed to detect chromosomal problems, such as Down syndrome and other genetic disorders such as cystic fibrosis and sickle cell disease. Results of analysis are usually ready in 7 to 10 days, and are 99 percent accurate.

What you need to know before you have CVS

• CVS may be uncomfortable, but it is not usually painful. You may feel a pinch and some pressure, similar to a Pap smear.
• CVS increases the normal risk of miscarriage by approximately 1 percent. This means that 99 of 100 women will have no problem. You can generally return to normal activity within two days.
• CVS cannot detect some neural tube defects, such as a mild spina bifida. Some women who choose CVS may also need a simple blood test (MSAFP) during their fourth or fifth months of pregnancy.
• Many insurance companies cover CVS. If you need help in determining this, speak with your Woman’s healthcare team.