Chorionic villus sampling (CVS) is a test done during pregnancy to diagnose certain chromosomal problems or genetic diseases.
By examining cells from your placenta, called chorionic villi, through a biopsy, we can determine if your baby has genetic conditions that run in families, such as Tay-Sachs disease or hemophilia, and disorders like Down syndrome that affect chromosomes.
This outpatient prenatal test can give vital information about their baby’s well-being to women with potentially high-risk pregnancies.
Why is chorionic villus sampling performed?
Your doctor may recommend the procedure for a variety of reasons, including:
- Age – As you get older, you have a greater chance of having a baby with a genetic condition.
- You or your partner carry an abnormal gene – This could potentially be passed down to your baby.
- Family history – If your family has a history of genetic disorders, these could also be passed on to the baby.
- Pregnancy history – If you’ve previously had a child with Down syndrome or another chromosome problem, you’re at higher risk for having another.
- Abnormal screenings – A sampling might be necessary if one of your earlier prenatal tests determines your baby has a higher risk of having an issue.
You might choose to have a chorionic villus sampling instead of an amniocentesis, which also diagnoses some of the same disorders, because CVS can be performed earlier in pregnancy — most often between 10 and 13 weeks — giving you more time to explore options.
What to expect during chorionic villus sampling
It’s done one of two ways — through the belly or through the cervix — depending on the position of the placenta and baby:
Through the belly (transabdominal)
First, you’ll be given a numbing medicine through an injection. This might sting a bit.
Then, a needle is inserted through the belly and into the placenta. The needle collects the sample of chorionic villus cells. The baby’s vitals will be monitored throughout the test.
Through the cervix (transcervical)
After a speculum is inserted in the vagina, your doctor will clean the cervix with an antiseptic.
Then, the provider will use an ultrasound placed on your abdomen to guide a thin tube called a catheter through the cervix and into the placenta. When the catheter is in the right place, the sample of cells will be collected. You might feel some cramping because of the catheter.
With both versions of the procedure, it’s recommended to refrain from strenuous activity and sex for a day or two following the test.
Results of chorionic villus sampling
It generally takes up to one to two weeks to get results. Genetic counseling may be made available to help you understand the results and your options moving forward.
Depending on the results, our Maternal Fetal Medicine experts will discuss any surgeries, treatments or medicines your baby might need during pregnancy and after he or she is born.
There is a risk of inconclusive results and the potential need for follow-up testing.
Our Services
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Cell-free DNA test A simple blood test, this screens for genetic conditions, such as Down syndrome.
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Fetal echocardiogram A special ultrasound of your baby’s heart, this tool allows specialists to diagnose certain heart defects.
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Fetal kick counts Doing this exercise can provide a simple way to check on the baby during the later months of pregnancy.
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Group B Strep test This is a swab test to check for a bacteria strep infection during the later weeks of pregnancy.
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Nuchal translucency This ultrasound measures the collection of fluid under the baby’s skin at the back of the neck.
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Quad screening This blood test screens for open neural tube defects and other possible problems.