Genetic specialists analyze the tissue. It can help them predict early in a pregnancy whether the baby has a chromosome disorder, such as Down syndrome. CVS is a relatively new alternative to amniocentesis.
Amniocentesis is a procedure in which fluid is sampled from the sac surrounding the baby.
CVS can be done several weeks earlier than amniocentesis. It is used to test for many of the same disorders that amniocentesis tests for. Unlike amniocentesis, however, CVS cannot detect neural tube and spinal defects. Your family or you have a history of a pregnancy or child with a chromosome problem, such as Down syndrome or birth defects. Your family has a history of mental retardation or inherited disease such as Tay-Sachs, sickle cell anemia, or cystic fibrosis.