Oxford Women's Health
Chorionic Villus Sampling
Chorionic villus sampling (CVS) is used to test for genetic disorders, such as Down’s syndrome, and involves taking a small sample of the chorionic villi, which are the tiny units that make up the placenta. The placenta is the organ that grows on the inner lining of your uterus (womb) through which nourishment and oxygen pass to your foetus (unborn baby). The chorionic villi have the same chromosomes as your foetus and DNA analysis will determine if your unborn child has any genetic abnormalities.
Using ultrasound as a guide, the sample is obtained by inserting a cannula up through the vagina and cervix (transcervical) or by inserting a needle in through your stomach (transabdominal).