Chorionic Villus Sampling (CVS)
Chorionic Villus Sampling (CVS) is a prenatal test that involves taking a tiny tissue sample from placenta where the fetus develops. The tissue is tested to diagnose whether there is any chromosome abnormality such as Down’s syndrome. The test generally is performed at least two months after a woman’s last menstrual period.
Preparation for CVS Test
The CVS test does not require the use of anesthetics, but it may need soporific injection into vein. Before the test, a patient must abstain from food and drinks for at least six hours. For safety reason, a CVS test is conducted in operation theatre and with the help of an anestheticist.
CVS Procedures
After the patient falls into her sleep, she will be subject to an ultrasound. From the ultrasound, a doctor will be able to estimate the exact age of pregnancy, the number of fetus, as well as
heartbeat rate, posture and position of the fetus. Then, the doctor will clean the patient’s external sex organ with disinfectant solution and use an equipment to enlarge the vagina for a clear view of womb. When the womb is in sight, the doctor will extract a tiny tissue from the placenta through a small plastic tube. All these procedures will be made while the fetus is in sight from the ultrasound to ensure that the procedure will not harm the fetus, its umbilical cord or placenta.
Then, the tissue sample will be sent to a lab test and the result will be available within three days.
After CVS-Test, you should
- Take full rest for at least one day
- Take as much rest as possible for at least one following week
- Avoid carrying heavy objects, too much walking and long-distance travel
- If abnormalities such as increased bleeding from vagina, amniotic fluid from vagina, fever and severe stomachache arise, please rush to a see a doctor.
CVS Benefits Abnormality in the fetus can be detected as early as the pregnancy is just two months.
Risks of CVS Tests
- Abortion ~ 1 – 3 %
- A minimal risk that the plastic tube may come into contact with the fetus, its placenta and umbilical cord
- Infections
- Pre-mature Births
- Bleeding from torn placenta or bleeding from blood vessels inside placenta
- If mixed with the mother’s blood, the test might yield inaccurate results.
