Chorionic Villus Sampling

Chorionic villus sampling (CVS) is a procedure for genetic testing that provides information on fetal karyotype, such as detecting Down’s syndrome, and certain genetic syndromes such as sickle cell disease or Tay Sach’s disease. CVS is typically performed in the first trimester between 11-13 weeks gestation by a trained specialist and can provide earlier results than those provided by amniocentesis which is typically performed in the second trimester between 16-20 weeks gestation.

CVS is an ultrasound-guided procedure that samples tissue (chorionic villi) in the placenta outside the amniotic sac. The genetic material in the placental cells are typically the same genetic material in fetal cells. The procedure can be performed via the abdominal wall (transabdominally) or via the cervix (transcervically), depending on the location of the placenta. There is a small risk of bleeding, infection and miscarriage. Patients should understand the risks of the procedure and should discuss the potential risks and benefits with their health care provider and a genetic counselor.