Do You Need a CVS Prenatal Test?
Chorionic villus sampling lets your doctor test for chromosomal abnormailties, such as Down Syndrome. Find out if this test is right for you.
So CVS is stands for chorionic villus sampling. It is also a needle procedure like the amniocentesis, but it can be done earlier in pregnancy typically 9 to 14 weeks as the window of time when CVS is done. And it samples from cells from the early placenta. If the couple is already decided they do want to have a more definitive diagnosis and do invasive testing, they may opt to do CVS because you have the result sooner. CVS and amniocentesis these days both test for chromosomes, but there's also an array of other disorders that can now be tested for and one of the hard part of the couple is to decide in some cases is whether to do these expanded tests or not. Because those results can be somewhat confusing in terms of what the information is. If they're all negative, you feel great. If some of these are positive, it may not quite sure in every case what that really means for your baby. It does seem that in the most experienced hands, the risk for CVS is probably the same as the risk for amniocentesis, but generally speaking the risk for CVS is quoted to be a little bit higher than the risk for amniocentesis. Technically, it probably relates to people who don't want anymore amnios. Much like the amniocentesis, a needle is inserted that is like drawing blood. It's not so comfortable, but it's typically brief and the patients often tolerate it quite well. CVS is mostly done abdominally, although there are sometimes depending on the location of the placenta sometimes. It may also be done vaginally and so the needle is introduced under ultrasound guidance and the sample is taken from the site of the early placenta. We often tell patients to expect-- to wait somewhere in the 10- to 14-day range. For chromosome analysis, results are 100% accurate.