Chorionic Villus Sampling (CVS)

Definition - What does Chorionic Villus Sampling (CVS) mean?

Chorionic villus sampling (CVS) is a test completed in the early stages of pregnancy to detect genetic conditions or abnormalities in a fetus. The results can guide treatment for the mother or impact pregnancy management decisions for the woman or couple. The CVS is completed within the first 10-13 weeks of the pregnancy and is the earliest fetal test capable of indicating genetic abnormalities. However, CVS may increase the risk of miscarriage.

FertilitySmarts explains Chorionic Villus Sampling (CVS)

The CVS can be completed transcervically (through the cervix) or transabdominally (through the abdomen). The CVS requires removing a sample of the chorionic vili, finger like projections comprised of placental tissue that contain the same genetic makeup of the fetus. The transcerivcal procedure requires access to the placenta through the cervix, using a long tube and suction to remove the sample. The transabdonimal procedure requires the insertion of a long, thin needle through the stomach. Both procedures are guided by ultrasound, which provides a view of the interior of the uterus and the fetus’ position. A CVS is most often performed when signs or past history indicates a severe or life threatening condition may be present. These include:

  • Positive or concerning results from a prenatal screening
  • A previous pregnancy with chromosomal conditions
  • Maternal age of 35 or older
  • Family history of genetic diseases or conditions
The primary risk of CVS is miscarriage. It is also possible to spread an infection to the uterus during the procedure. CVSs completed prior to 10 weeks of gestation may cause birth defects.


The results of CVS procedures may provide information that impacts a woman or couple’s feelings on a pregnancy. Any individual who decides to complete the procedure should be prepared for adverse results, and have the support and education necessary to make decisions as needed.

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