Definition for Chorionic villus sampling
From Biology Forums Dictionary
1) A technique associated with prenatal diagnosis in which a small sample of the fetal portion of the placenta is removed for analysis to detect certain genetic and congenital defects in the fetus.
2) Chorionic villus sampling is a form of prenatal diagnosis to determine chromosomal or genetic disorders in the fetus. It entails sampling of the chorionic villus (placental tissue) and testing it for chromosomal abnormalities, usually with FISH or PCR. Chorionic villus sampling usually takes place at 10–12 weeks' gestation, earlier than amniocentesis (14–16 weeks).