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Chorionic Villus Sampling (CVS)

How It Is Done continued...

An ultrasound will be used to help your doctor guide the catheter through your cervix to the placenta. An ultrasound device (transducer) that gives off and picks up sound waves will be passed over your belly. The reflected sound waves are sent to a computer to make a picture of the uterus, your baby, and the placenta on a screen. Your baby's heart rate can also be checked during the procedure using ultrasound. For more information, see the topic Fetal Ultrasound.

When the catheter is correctly placed, a sample of chorionic villus cells will be collected.

After the sample is collected, your doctor may listen to your baby's heart rate and check your blood pressure, pulse, and breathing.

How It Feels

If you have the procedure through the belly, you will feel a short, sharp sting from the needle used to give the numbing medicine. There is usually no pain when the collecting needle is put in the belly. You may feel some cramping when the needle is inside your uterus.

Most women do not find the transcervical procedure painful. You will probably find that this test feels similar to having a Pap test or pelvic examination. You may feel some cramping when the catheter is guided through your cervix.

Risks

Chorionic villus sampling (CVS) can cause cramping, leakage of amniotic fluid, and vaginal spotting, which goes away in 1 to 2 days. You may feel some soreness where the needle was put in if you had the belly procedure done.

CVS also increases the chance of:

  • Developing a uterine infection.
  • Having a miscarriage. Overall, one study showed the risk of miscarriage from CVS is about 1 in 400 when done by a highly trained provider.1
  • Having a baby with arm or leg abnormalities though the chance of this happening is very low, especially when the test is done after 10 weeks.

Chorionic villus sampling has a very small chance of causing bleeding that could result in mixing your blood and your baby's. If you have Rh-negative blood, you will be given the Rh immunoglobulin vaccine (such as RhoGAM) to prevent Rh sensitization which could harm your baby if he or she has Rh-positive blood.

After the procedure

It is normal to have mild cramping, leakage of a small amount amniotic fluid, and vaginal spotting for the first day or two after the procedure. Call your doctor immediately if you have:

  • Moderate or severe belly pain or cramping.
  • More leakage of amniotic fluid from your vagina.
  • More vaginal bleeding than spotting, or bright red bleeding.
  • Chills or a fever.
  • Dizziness.
  • Redness or swelling at the needle site if you had a belly procedure.

WebMD Medical Reference from Healthwise

Last Updated: April 04, 2012
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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