Chorionic villus sampling (CVS) is an invasive prenatal diagnostic procedure used for fetal karyotype testing. During the procedure, performed between the 10th and 13th weeks of pregnancy, a long need is inserted through the mother’s abdomen and into the uterus to collect a sample of the baby’s cells from the chorionic villi. Chorionic villi are the tissues found within the placenta, the organ that forms during pregnancy to nourish the developing baby.
The sample is sent to a lab, where the baby’s cells are studied in order to diagnose or rule out prenatal conditions.
A CVS may be recommended in cases where there is an expected or increased risk of aneuploidy or other genetic conditions. A CVS is an invasive procedure; it does come with risk. The risk for miscarriage following a CVS is 1 in 100.