Q: What is CVS?

A: Chorionic villus sampling (CVS) is a prenatal test usually done between the 10th and 12th weeks of pregnancy. It entails a small sample of cells called chorionic villi (tiny parts of the placenta that are formed from the fertilized egg, so they have the same genes as the baby) taken from the placenta. Simply put, it is a photograph of the chromosomes from a single cell.

Q: What are you testing for?

A: Chromosomal abnormalities, such as Down syndrome.

Q: Who should take this test?

A: Anyone with certain risk factors for having a baby with a birth defect or genetic disease. These risks include:

• Abnormal results from a prenatal screening test.
• A chromosomal abnormality in a previous pregnancy.
• Being age 35 or older.
• A family history of a specific genetic disorder, or you or your partner is a known carrier of a genetic disorder.

Q: Is it safe?

A: Overall, chorionic villus sampling has a one in 100 risk of miscarriage. The risk of miscarriage appears to be slightly higher when the tissue sample is taken through the cervix rather than the abdomen. The risk of miscarriage also increases if the baby is smaller than normal for his or her gestational age.