Table of Contents
- Overview
- Results
- Risks
- Prevention
- Images
Chorionic villus sampling (CVS) is the removal of a small piece of placenta tissue (chorionic villi) from the uterus during early pregnancy to screen the baby for genetic defects.
How the test is performed
CVS can be done through the cervix (transcervical) or through the abdomen (transabdominal). The techniques are equally safe when done by a provider with experience, although miscarriage rates are slightly higher when done through the cervix. The health care provider will use ultrasound to pick the safest approach and as a guide during sampling.
An
The transcervical procedure is performed by inserting a thin plastic tube through the vagina and cervix to reach the placenta. The provider uses ultrasound images to help guide the tube into the appropriate area and then removes a small sample of chorionic villus tissue.
The transabdominal procedure is performed by inserting a needle through the abdomen and uterus and into the placenta. Ultrasound is used to help guide the needle, and a small amount of tissue is drawn into the syringe.
The sample is placed in a dish and evaluated in a laboratory.
How to prepare for the test
Your health care provider will explain the procedure, its risks, and alternative procedures such as amniocentesis. Genetic counseling is recommended prior to the procedure. This will allow you to make an unhurried, informed decision regarding options for prenatal diagnosis.
You will be asked to sign a consent form before this procedure, and you may be asked to wear a hospital gown.
Images
Review Date: 06/05/2010
Reviewed By: Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of
Physician Assistant Studies, University of Washington, School of
Medicine; Susan Storck, MD, FACOG, Chief, Eastside Department of
Obstetrics and Gynecology, Group Health Cooperative of Puget Sound,
Redmond, Washington; Clinical Teaching Faculty, Department of
Obstetrics and Gynecology, University of Washington School of
Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director,
A.D.A.M., Inc.
A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)
