How Is the CVS Test Performed?
Before undergoing a CVS prenatal test, appropriate genetic counseling, including a detailed discussion regarding the risks and benefits of the procedure, are recommended. At the time of initial consultation and counseling, an ultrasound exam will be performed to confirm gestational age (the development stage of the embryo) and the location of the placenta. This is done so that CVS can be performed at the appropriate gestational age (which is usually 10 to 12 weeks from the woman’s last menstrual period). There are two ways to collect chorionic villi from the placenta: through the vagina or through the abdomen. To collect cells through the vagina, a speculum is inserted (in the same way as a Pap test). Then a very thin, plastic tube is inserted up the vagina and into the cervix. With ultrasound, the tube is guided up to the placenta, where a small sample is removed. To collect cells through the abdomen, a slender needle is inserted through the woman’s abdomen to the placenta, much like
