Amniocentesis and Chorionic Villus Sampling (CVS)

If you are pregnant and did not undergo IVF/PGT, there are two options for diagnostic genetic testing. These are chorionic villus sampling (CVS) and amniocentesis. A diagnostic genetic test tells you (with as much certainty as possible) whether the baby actually has a specific genetic disorder.

Amniocentesis is a procedure in which a thin needle is used to withdraw a small amount of amniotic fluid. Amniotic fluid, which is the fluid that surrounds the baby inside the uterus, contains fetal cells and various proteins. This test is typically performed between 15 to 20 weeks of pregnancy, but can be done up until you give birth. There is a small risk of miscarriage (0.11%) with amniocentesis. Other risksinclude leakage of amniotic fluid or slight bleeding however these stop on their own in most cases.

Chorionic villus sampling (CVS) is a procedure where a sample of tissue is removed from the placenta. It is often thought of as a placental biopsy. The sample can be taken through the cervix (transcervical) or the abdominal wall (transabdominal). While a CVS and amniocentesis can give you the same information, the main advantage of CVS is that it is performed earlier, typically between 10 to 13 weeks of pregnancy. The risk of miscarriage may be slightly higher with CVS (0.22%)

Testing for specific genetic conditions, such as ALD, can be performed on the sample obtained by CVS or amniocentesis. A number of other types of testing may also be performed. Result times vary by lab and by what tests are performed but typically range from 1-3 weeks . Your doctor and/or genetic counselor can provide guidance on your choices and options and select the tests that are best for you.