Chorionic villus sampling is a test that is done during early pregnancy to test for chromosomal problems in the fetus. It involves removing chorionic villi from the placenta. The placenta is the organ that provides nutrients and oxygen to the baby during pregnancy. It also removes waste from the baby’s blood. Chorionic villi is the tissue that makes up most of the placenta. The test is done during the 9th-13th weeks of pregnancy.

Nine Week Old Fetus in Utero
Nine Week Old Fetus in Utero
Copyright © Nucleus Medical Media, Inc.

Chorionic villi contains valuable information about the baby’s genes. By testing chorionic villi, the doctor can find out if the baby has a chromosomal abnormality, like Down syndrome. The test can also detect genetic disorders, like cystic fibrosis. It cannot detect neural tube defects, such asspina bifida.

This test may be considered when:

  • Other tests, such as a first trimester ultrasound revealed abnormal results
  • A prior pregnancy had a chromosomal abnormality
  • The mother is 35 years old or older
  • You or your partner is a carrier for a genetic disorder
  • There is a family history of a genetic disorder

Although a test showing a healthy baby without a genetic disorder is ideal, you will need to be prepared if the results show otherwise. If the test shows that your baby may have a genetic disorder, it may require you to make tough decisions regarding your pregnancy, such as whether or not to continue it. If you continue with the pregnancy, you will need to address concerns, such as planning for a child with special needs. Your doctor can help you understand the pros and cons of having this test, as well as talk about your options after you know the results.