Chorionic villus sampling (CVS) is a prenatal test employed to analyze sample tissue from the placenta for chromosomal abnormalities and other genetic issues in the fetus. The chorionic villi are tiny finger-like placental tissue that stick out and contain the same genetic material as the fetus.
For most women, CVS is performed between 10 to 13 weeks of pregnancy.
Types of CVS Procedures
There are two types of CVS procedures:
- Transabdominal – During this procedure, a needle is injected through the abdomen and uterus to obtain the placental tissue.
- Transcervical – During this process, a catheter is put into the placenta through the cervix to extract the tissue sample.
Why Women Receive CVS
CVS is recommended to test for genetic and chromosome abnormalities during the first trimester of pregnancy. Women elect to undergo CVS for several reasons, including:
- A screening test for a fetal genetic condition is positive (such as cell free fetal DNA screening, or nuchal translucency screening)
- History of an affected child with a genetic disease, metabolic disorder, or chromosomal abnormalities
- Recent ultrasound found abnormalities or questionable results
- Her and her partner are carriers of a genetic condition
Advanced maternal age (35 or older) used to be the most common indication for CVS, but with more sensitive screening tests, women over 35 are no longer told that they must undergo this test.
Although these are the most common reasons for CVS, there may be various reasons why your doctor recommends CVS.
CVS Procedure Risks
Although CVS procedures are relatively safe, it carries some risk since it’s an invasive procedure. The risk of miscarriage from the procedure is less than 1% (approximately 1 in 500).
Carnegie Imaging for Women blogs are intended for educational purposes only and do not replace certified professional care. Medical conditions vary and change frequently. Please ask your doctor any questions you may have regarding your condition to receive a proper diagnosis or risk analysis. Thank you!