Chorionic villus sampling (CVS)

Chorionic villus sampling (CVS) can be done in 2 different ways. In transcervical CVS (shown on the left), the doctor inserts a tube through the vagina to take the sample of placenta, which is also called the "chorionic villus." In transabdominal CVS (shown on the right), the doctor inserts a needle straight into the belly. In both ways, the doctor uses ultrasound images to guide where the tube or needle goes.