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Chorionic Villus Sampling (CVS) |
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Written by Administrator
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Tuesday, 26 December 2006 |
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One way of obtaining fetal tissue is to take a small amount of the placental tissue from within the uterus. Placental tissue should have the same genetic composition as the fetus. A needle is inserted into the placental attachment to the uterus and a small amount of tissue is removed and sent for analysis.
The placenta can be approached either through the cervix or through the mother's abdominal wall. This procedure can be performed at 10-12 weeks, much earlier than routine amniocentesis. The results are available in about 5-10 days, sooner than with routine amniocentesis. The specimens obtained from this procedure can be contaminated with maternal tissue about 1% of the time (compared to about 0.2% in amniocentesis). This can confuse interpretation of the genetic tests. There are also rare circumstances when the abnormalities seen in the placenta may not be present in the fetus. Not only do you need a experienced professional performing the test, you also need one who can accurately interpret the test results. Having CVS increases the risk of fetal loss by about 1.2% over your risk without the procedure. Your actual risk is dependent on the skill of the person doing the procedure and your specific condition. There have been concerns about the procedure itself causing malformations of the legs and arms. This risk seems to be about 0.03% and is probably greater the earlier the procedure is performed. |
