Chorionic villus sampling (CVS) is a pregnancy related test that is performed to check whether the fetus has any genetic abnormalities. A small tissue sample from the placenta is taken for examination. This sample is made up of the same cells as that of the fetus and so, it is sent to the lab to be tested.
Who can take this test?
This test is only recommended to women who have a risk of carrying a baby with genetic anomalies or other serious conditions. Your doctor may suggest this test, if you or your partner has someone with a rare disease in the family or you may have had a previous baby with a genetic disorder. In case, your ultrasound scan results came out as abnormal, you may have to go for CVS. If you are 35 years or above around the time of your delivery, then your chances of having a baby with birth defects or other conditions are said to be high.
There are two ways of performing CVS. When this test is performed through abdomen, it is known as transabdominal chorionic villus sampling and when the test is done through cervix, it is called as transcervical chorionic villus sampling. Both the procedures involves using a thin needle to extract the sample cells, while using ultrasound as guide.
Since CVS is an invasive process, there are certain side effects associated with it. These could range from mild to severe.
CVS Risks and Side Effects
Common side effects
- You may experience cramping during the sample extraction. This may continue for sometime after the procedure completion, but goes away in a few hours. It is same as that of the cramping you experience during your menstrual period.
- There may be slight bleeding for two or more hours, but stops later and it should not get heavy.
- There may be some leaking of amniotic fluid.
- You may feel slightly dizzy after the test.
Rare side effects
- Miscarriage has been reported in some cases after CVS procedure. This is known to be one in 100 pregnancies.
- There is a risk of infection in the uterus, which in turn is associated with miscarriage.
- If the test is done prior to completion of 9 weeks, it is known to increase the risk of limb defects in babies at birth.
- The procedure can lead to small amount of baby’s cells entering the blood vessels of the mother. If the baby happens to be Rh-positive and the expecting mom is Rh-negative, then the mother’s body tends to make antibodies as in response to fight against foreign matter. These antibodies can cause severe complications and may even be fatal to the fetus.
- With CVS, there are risks of haemorrhage and preterm labor.