Chorionic Villus Sampling (CVS)

Test Overview

Chorionic villus sampling (CVS) is a test that can find certain problems with your fetus. These include many diseases that run in families (genetic conditions) and chromosome problems. It is done during early pregnancy, most often between the 10th and 13th weeks.

Chorionic villi are tiny finger-shaped growths found in the placenta. The chorionic villus cells have the same genetic material as the baby's cells. During CVS, a sample of the chorionic villus cells is taken. The sample is collected by putting a thin tube (catheter) through the vagina or by putting a long, thin needle through the belly. Ultrasound is used to guide the catheter or needle to the right spot.

CVS can find many genetic conditions. It can also find chromosome problems, such as Down syndrome. CVS can't find neural tube defects.

CVS is done earlier in pregnancy than amniocentesis (usually done at 15 to 20 weeks). And the results of CVS are available sooner. This gives you more time to make decisions about your pregnancy or plan for the future.