A method of prenatal testing in which fetal cells from the fetal side of the placenta (chorionic villi) are extracted and analyzed for chromosomal and biochemical defects.

Chorionic villi sampling is a method of prenatal diagnosis in which a small piece of fetal placenta, or chorionic villi, is removed early in pregnancy for genetic testing.

An invasive prenatal test that looks for genetic abnormalities by sampling a piece of the placenta. Usually done at 10 to 12 weeks' gestation.

A medical procedure in which a catheter is inserted through the vagina and cervix to obtain a small sample of tissue from the edge of the chorion to diagnose possible defects of the developing fetus.

A means of testing the fetus for various abnormalities, such as congenital defects, blood disorders, and inborn errors of metabolism. This test can be performed during the first trimester of pregnancy, but is easier to carry out between the 14th and 16th weeks of pregnancy.

A prenatal test that scans for genetic abnormalities.