CVS (Chorionic Villus Sampling)

CVS is a prenatal test that helps you learn if a fetus has health problems. The test is most often done after 10 weeks of pregnancy. Discuss with your healthcare provider whether CVS is right for you.

Side view of female pelvis showing transcervical chorionic villus sampling.

Should you have CVS?

If the fetus has a higher than normal chance of birth defects or other problems, you may want to have this test. The following risk factors can increase chances of fetal health problems:

  • You’re 35 or older.

  • There’s a history of inherited (genetic) problems in your family.

  • Other tests have shown that the fetus may have health problems.

How CVS is done

The test can be done through your belly (transabdominal). Or it may be done through your cervix (transcervical). It is common to feel some cramping during and after the CVS test.

Transabdominal CVS

  • The healthcare provider puts a needle through your belly (abdomen) and into the uterus.

  • The provider uses ultrasound to guide the needle into place near the placenta. Ultrasound is sound waves that make an image on a screen.

  • The provider takes a small amount of tissue with a syringe.

Transcervical CVS

  • First, the fetus is located with ultrasound.

  • The healthcare provider puts a thin tube into your vagina and guides it to your uterus. 

  • The provider removes a small amount of cells from the tissue that will become the placenta (chorionic villi) by gentle suction. 

You can go home right after the test. But you may need to take it easy for a day or so.

When to call your healthcare provider

Call your healthcare provider right away if you notice:

  • Severe pain or cramping

  • Vaginal bleeding (spotting)

  • Fever or chills

  • Fluid leaking from your vagina

Getting test results

You’ll learn your CVS results a few days after the test. CVS is a very accurate test, but in a few cases, results may be inconclusive. Most results are normal. Even if yours aren’t, it doesn’t always mean there’s a problem. You and your healthcare provider can talk about other tests or special care you may want.