CVS is one prenatal diagnostic procedure that is typically done between 11 and 12 weeks. It involves removing a sample of the placenta. For most diagnosis the cells have to be cultured for a period of time before the analysis is done. The standard test done on the sample is analysis of the chromosomes. Down syndrome is just one of the chromosomal abnormalities evaluated. Other testing may be done. The genetic counselor will be play an important role in discussing your risks and appropriate testing that would be recommended. You might want to refer to the link for Genzyme


An ultrasound is done to evaluate the fetal anatomy, the weeks of pregnancy and the location of the placenta. Depending on the placental location one of two methods are used. One method is through the abdomen the other is through the cervix. When done through the abdomen, the skin is cleaned with betadine (unless there is an allergy to Iodine), local anesthetic is injected into the skin (unless allergic to lidocaine or you decline the anesthetic) under ultrasound guidance the needle is inserted through the skin and the uterus into the placenta. Tissue is then removed through the needle. When done through the cervix a speculum is placed in order to visualize the cervix (similar to having a PAP smear), under ultrasound guidance a catheter is inserted through the cervix to the placenta and tissue removed. The fetal heartbeat is then shown to you. If your blood type is Rh NEGATIVE then you will receive an injection to prevent you from forming antibodies against the blood of the fetus.


Occasionally you may have some cramping, slight bleeding or fluid leakage. A majority of women have no complications. The pregnancy loss rate is similar to the risk of amniocentesis. It is recommended that you rest the day of the procedure and for the next 24 hours you do not lift more than 10 pounds, exercise or have intercourse.


Typically it takes 7-10 days for the results. It may take longer of other tests are done or if the cells are growing slower than usual. One may get preliminary results in 1-2 days with special type of testing. The genetic counselor can guide you with more information regarding this option. Most insurance companies do not cover the testing done for preliminary results.

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