Chorionic villus sampling
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Chorionic villus sampling (CVS) is a form of prenatal diagnosis to determine genetic abnormalities in the fetus. It entails getting a sample of the chorionic villus (placental tissue) and testing it. It is generally carried out only on pregnant women over the age of 35 and those who have a higher risk of Down syndrome and other chromosomal conditions.
The advantage of CVS is that it can be carried out at 10-12 weeks of pregnancy, earlier than amniocentesis (which is carried out at 15-18 weeks). However, it is more risky than amniocentesis, with a 1 in 100 to 200 risk that it will cause a miscarriage.
External links
- March of Dimes (http://www.marchofdimes.com/pnhec/159_521.asp)
- Medline Plus (http://www.nlm.nih.gov/medlineplus/ency/article/003406.htm)