Medical Health Encyclopedia

Chorionic villus sampling

You will be asked to sign a consent form before this procedure, and you may be asked to wear a hospital gown.

The morning of the procedure you may be asked to drink fluids and refrain from urinating to fill your bladder, which allows adequate visualization so the sample may be taken.

How the test will feel:

Text Continues Below

---

The ultrasound is not uncomfortable. A clear, water-based conducting gel is applied to the skin to help with the transmission of the sound waves. A handheld probe called a transducer is then moved over the area. In addition, your health care provider may apply pressure on your abdomen in an attempt to manually locate the position of your uterus.

The antiseptic cleansing solution will feel cold initially and may irritate your skin if it is not removed after the procedure. Some people are allergic to Betadine. Notify your health care provider if you are allergic to Betadine or if you have any other allergies.

Patients report that the actual sampling feels similar to a Pap smear, where there is some discomfort and a feeling of pressure. There may be a small amount of bleeding following the procedure.

An obstetrician can perform this procedure in about 5 minutes, after the preparation.

Why the test is performed:

This test is a way of detecting congenital (present from before birth) defects. The sample is used to study the DNA, chromosomes, and enzymes of the fetus and can be done earlier than amniocentesis, about 10 to 12 weeks after your last menstrual period.

Test results from a CVS are obtained within 1 to 2 weeks, whereas amniocentesis results may take as long as a month. Earlier diagnosis of congenital defects may relieve some of the concerns of your family, especially if a therapeutic abortion is under consideration.

Chorionic villus sampling does not detect neural tube defects. If neural tube defects or Rh incompatibility are a concern, an amniocentesis will be performed.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2004 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.