Chorionic villus sampling

Chorionic Villus Sampling (CVS)

Chorionic villus sampling (CVS) is a prenatal diagnostic procedure used to detect genetic or chromosomal abnormalities in the fetus. It is a popularly used procedure for pregnant women who are at risk of having or having a baby with congenital birth defects.


Prior to CVS, the parents will meet with a genetic counselor to determine the risks and benefits of the procedure. The physician will also review the patient's health history and explain the procedure. The mother may be asked to have a full physical exam, including a Pap smear or ultrasound.


The CVS procedure is usually performed by a physician under ultrasound guidance. The procedure may be done transabdominally, through the abdomen, or transvaginally, through the vagina. The physician will use a fine needle to take a small sample of chorionic villi (placenta cells) from the placenta. The sample will then be sent to a lab for analysis.


There are two types of CVS: transcervical and transabdominal. Transcervical CVS is done through the cervix, while transabdominal CVS is done through the abdomen. Transcervical CVS is generally used earlier in the pregnancy (10-14 weeks), while transabdominal CVS is often done later (14-20 weeks).


CVS does carry a small risk of miscarriage. The risk is estimated to be about 1%. Other risks include infection, bleeding, and cramping.


CVS is used to diagnose genetic disorders in unborn babies. It can detect Down syndrome, Tay-Sachs disease, muscular dystrophy, thalassemia, and several other genetic disorders. It is also used to determine the sex of the baby if desired.


CVS is typically performed between 10 and 14 weeks of pregnancy. It can be done earlier or later, depending on the individual situation. The results of the CVS will be available within a few days to a few weeks.