What are the Risks of Chorionic Villus Sampling?

Chorionic Villus Sampling (CVS) is an excellent diagnostic tool for expecting parents, since it can be used to identify potential problems with a fetus at a very early stage. However, the procedure does carry some risks, as does any invasive diagnostic procedure. Women who are considering Chorionic Villus Sampling should discuss the risks of the procedure with their doctors, carefully weighing the benefits against the potential cost.

When Chorionic Villus Sampling is performed, a small sample of the placenta is removed for analysis. Since the placenta contains fetal material, it can reveal genetic defects which may lead to problems for the fetus. This prenatal test can be performed as early as 11 weeks into the pregnancy, which is one of the reasons why parents choose it, since they can have concrete information about the health of the fetus early on.

One of the biggest risks of Chorionic Villus Sampling is miscarriage. In one to 100 or 200 cases, the procedure is linked with miscarriage. In an experienced clinic, this rate may go down to one in 300 to 400. If you are concerned about the risks of Chorionic Villus Sampling, it is a good idea to work with a very experienced clinician; do not be afraid to ask a doctor about the rate of complications he or she has personally experienced.

The procedure also has a number of side effects, some of which can be risky. Cramping is very common, as is light spotting and some pain. A fever and chills may accompany Chorionic Villus Sampling, and in some cases leaking of amniotic fluid occurs. Leakage is another one of the risks of Chorionic Villus Sampling, since it can lower amniotic fluid to a dangerous level for the infant.

If a mother is Rh negative, one of the risks of Chorionic Villus Sampling is the mixture of her blood with that of the fetus, potentially causing an immune system reaction due to the incompatible blood types which are present. Hopefully, the blood type incompatibility has already been identified in earlier prenatal testing and the mother has received Rh immune-globulin, which will prevent this reaction.

When performed before 10 weeks, another of the risks of Chorionic Villus Sampling is the potential for missing fingers and toes in the newborn. For this reason, the procedure is only recommended for women who are at least 11 weeks pregnant. In addition, CVS is not recommended for women currently dealing with infections, women who have experienced abnormal bleeding, and women carrying twins. It is also important to remember that false positives do occur with CVS, so it is a very good idea to confirm any positive results with additional testing before making medical decisions.