Prenatal diagnostic techniques. Chorionic villus sampling.

Chorionic villus sampling (CVS) is a new prenatal diagnostic technique which is performed in the first trimester of pregnancy. Traditional methods of prenatal diagnosis, including amniocentesis and fetoscopy, must be performed in the midtrimester. In concert with the development of DNA methods of fetal cell analysis, first trimester fetal diagnosis utilizing CVS offers many advantages over traditional mid-trimester techniques. In addition, CVS may potentially allow therapeutic intervention to prevent or ameliorate some congenital defects.