What Is Chorionic Villi Sampling (CVS)?
CVS is a procedure performed in the first trimester of pregnancy to detect to detect birth defects by taking a sample of cells from parts of the placenta called the chorionic villi, which have the same genes as the fetus. CVS can detect most of the same defects as amniocentesis , but it cannot detect open neural tube defects. If you have CVS, you will want to consider having a blood alpha-fetoprotein (AFP) test later in your pregnancy to test for neural tube defects.
