Chorionic Villus Sampling (CVS)

Chorionic Villus Sampling (CVS) is a prenatal diagnostic test performed between 10 and 13.5 weeks of pregnancy to determine whether the fetus may have certain genetic or chromosomal conditions. CVS may be recommended if:

• The mother is age 35 or older

• A prenatal screening test indicates an increased risk

• An abnormality is detected on ultrasound

• There is a known inherited or genetic condition in the family

CVS involves collecting a small sample of chorionic villi, which are tiny projections of placental tissue that share the baby’s genetic makeup. The sample is obtained either through the cervix or the abdomen, depending on placental position. Ultrasound guidance is used throughout the procedure for safety and precision. The procedure typically takes only a few minutes. While most patients report mild pressure or cramping, any discomfort usually resolves within a few hours.

Although CVS is considered safe when performed by an experienced physician, it does carry potential risks. These may include miscarriage, bleeding, infection, membrane rupture, or—for Rh-negative mothers—possible Rh incompatibility.

Unlike amniocentesis, CVS cannot detect neural tube defects such as spina bifida. For this reason, patients who undergo CVS are offered a Maternal Serum Alpha-Fetoprotein (msAFP) blood test during the second trimester.

The collected sample is analyzed in a laboratory to evaluate for chromosomal abnormalities or specific inherited conditions. Results are typically available within 7–10 days. CVS is most commonly used to diagnose chromosome disorders such as Down syndrome (trisomy 21), trisomy 18, and trisomy 13. When indicated, it can also test for more than 200 genetic conditions, including cystic fibrosis, spinal muscular atrophy, fragile X syndrome, Tay-Sachs disease, sickle cell disease, and hemophilia.

Patients also have the option to request chromosomal microarray testing or whole genome sequencing, which can detect hundreds of additional genetic variations not identified through standard screening. Visit mytestingoptions.com for more information.