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CVS (Chorionic Villus Sampling)
10th through 12th week
Prior to electing chorionic villus sampling (CVS) at GIVF, you will meet with a Genetic Counselor to discuss the test. After reading the following information, write down any questions that you may have and take them to your appointment.
CVS is a specialized alternative test to amniocentesis. It involves removing a small amount of tissue called the chorionic villi, which is located on the outside of the fetal gestational sac and will later become the placenta. The chorion is a fetal tissue, and shares its genetic makeup with the fetus, not the mother. The chorion has many small, finger-like projections on its outer surface, and a few of these may easily be removed without disturbing the pregnancy. The chorionic villi cells may be used for chromosome analysis or other genetic testing. The chorionic villi cannot be used to test for open neural tube defects.
CVS is available at GIVF from 10.0 to 13.3 weeks of pregnancy. The CVS may be performed transabdominally by guiding a thin needle through the abdominal wall to the chorionic villi, then withdrawing a small amount of this tissue. (See next page A) Occasionally, particularly if the thickest location of the villi is in the lower portion of the uterus, the CVS is performed transcervically by using a thin flexible plastic catheter (hollow tube) which is guided through the cervical opening, somewhat like having a Pap smear done. This catheter is then used to remove a small amount of the villi. (See next page B).
Most women do not report the CVS procedure to be painful. It usually takes a minute or two to perform, and is commonly described as feeling like pressure rather than pain. Some women experience mild cramping for up to a few hours afterwards or rarely experience light spotting that usually goes away within a day or two.
Because the procedure involves going inside the uterus, there is a small chance of bleeding or infection. Any of these complications may cause a miscarriage. At GIVF, we have observed this risk to be approximately 1 in 200 (0.5%). GIVF is one of the most experienced centers in the world at performing this first trimester diagnostic test, having provided over 30,000 women with this early option.
If you are on blood thinning medications such as Lovenox or Fragmin, please contact a GIVF Genetic Counselor at least 2 days prior to your appointment for directions.
Diagnostic Testing: CVS (Chorionic Villus Sampling)
The most common reasons a CVS is performed are:
- Maternal age of 35 years or more at expected time of delivery
- An abnormal first trimester screen result
- Ultrasound finding suggesting a higher risk for a chromosome abnormality
- Previous pregnancy or family history of certain chromosomal or genetic disorders
- Pregnancies at risk for certain genetic conditions
- A desire to obtain accurate test results as early as possible in pregnancy
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