What is Chorionic Villus Sampling: Is It Better Than Amniocentesis?
If you’re at higher risk for having a baby with a chromosomal disorder or certain birth defect, your doctor may recommend chorionic villus sampling, or CVS.
A common genetic test, CVS is a first-trimester prenatal diagnostic test that involves taking a small tissue sample from the finger-like projections of the placenta, called the chorionic villi.
This sample contains the same genetic information as your baby, so it can be used to check for chromosomal conditions like Down syndrome and abnormalities such as cystic fibrosis and muscular dystrophy with a high degree of accuracy. (It can also determine the sex of your baby, so speak up if you don’t know want to know.)
Having this information can help you and your provider plan for the future, including choosing whether to move forward with the pregnancy, preparing yourself emotionally and determining what kinds of care or treatment your baby might need after she’s born.
Still, CVS testing isn’t for everyone — and it does come with some small risks. Here’s what you can expect if you’re considering the procedure, plus what you can learn from the results.
Who chorionic villus sampling is for
CVS testing is available to any pregnant woman — typically between weeks 10 and 13 of pregnancy. It’s not necessary for every mom-to-be, but your doctor may recommend CVS testing if you:
- Are over 35, and therefore at increased risk of carrying a baby with a chromosomal disorder
- Have a family history or are a known carrier of a specific genetic disease for which CVS tests
- Received uncertain results from a nuchal translucency screening, first-trimester blood tests or noninvasive prenatal testing (NIPT)
Keep in mind that even if your doctor recommends it, the decision to pursue CVS testing is entirely optional. If you’re having trouble deciding what’s right for you, your provider or a genetic counselor can help you weigh the risks.
Chorionic villus sampling vs amniocentesis
Amniocentesis is usually performed during the 15th week of pregnancy or later. CVS is usually performed between the 10th and 13th weeks of pregnancy.
Is one test better than the other?
The main benefit of CVS is that it can be done earlier in the pregnancy. It’s very accurate in detecting genetic abnormalities. But it does not detect some things that amniocentesis does. These include:
- Neural tube defects (involving the spinal column or brain).
- Birth defects.
- Rh incompatibility (when the mother has Rh-negative blood and the baby has Rh-positive blood).
Amniocentesis might be the best option if:
- You previously had a baby with a neural tube defect.
- You or your partner have a neural tube defect.
- The results of other tests during your pregnancy have been abnormal. This could include a blood screening test done in early pregnancy.
CVS may be better if you and your doctor want to know the test results during your first trimester.
Chorionic villus sampling cost
Chorionic villus sampling typically costs around $3,050. The procedure is usually done in an outpatient facility or in a doctor’s office. Costs can vary widely based on where you go for the procedure, ranging from $1,300 to $4,800.
