Chorionic villus sampling (CVS)

This test is not routinely performed but may be discussed with or offered to pregnant women who are at an increased risk of having a baby with certain chromosome disorders, such as Down syndrome, or genetic abnormalities, such as cystic fibrosis. Between the tenth and twelfth week of pregnancy, a chorionic villus sampling (CVS) procedure can be performed in which either a needle inserted through the woman’s abdomen or a tube inserted through the woman’s vagina and cervix is used to obtain a tissue sample from the placenta. These cells have the same genetic makeup as the fetus and are analyzed for chromosome disorders and gene abnormalities.