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Chorionic Villus Sampling (CVS) |
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Chorionic villus sampling (CVS) is a diagnostic procedure during which a sample of chorionic villi cells from the placenta are removed and tested for chromosomal abnormalities and genetic birth defects.
CVS is done at 10 to 12 weeks gestation and can test for diseases such as Down syndrome, Tay Sachs, and cystic fibrosis. However, CVS does not test for neural tube defects. CVS can also be used for paternity testing.
CVS is recommended for women who:
CVS is not recommended for women who:
There are two ways a physician can remove chorionic villi cells:
In TC CVS, the physician guides a thin catheter through the vagina and cervix and into the placenta where a small amount of tissue is obtained. Ultrasound is used to help guide the physician and decrease risk to the fetus.
In TA CVS, the physician guides a needle from the abdomen and into the placenta where a small amount of tissue is obtained. A local anesthetic may be used. The process is similar to amniocentesis. Just as with TC CVS, ultrasound is used to help guide the physician and decrease risk to the fetus.
After the procedure, you should plan to rest and refrain from intercourse and strenuous activity for the remainder of the day. You may experience cramping or pain and light spotting of blood. Call your healthcare provider is you experience fever, chills, or leaking amniotic fluid.
If you are carrying more than one fetus, the physician will take a sample from each placenta. This can be done using a combination of TA CVS and TC CVS. However, CVS is not recommended with twins.
Preliminary results may be available within two to four days, but may not be accurate. Final results are available about seven to 10 days after the procedure. CVS is highly accurate (~98-99%).
The primary risk with CVS is miscarriage. The risk of miscarriage is 1 in 100. An infection as a result of CVS is rare. When CVS is performed before 9 weeks, an increased risk of fetal limb abnormalities has been reported.
CVS can cause a small amount of fetal blood to leak into your circulation. This can be a problem if the mother is Rh-negative. If you are Rh-negative, you should receive RH immunoglobulin after the procedure.
If CVS results indicate that there may be a problem, additional testing and counseling is recommended.
CVS is done at 10 to 12 weeks gestation and can test for diseases such as Down syndrome, Tay Sachs, and cystic fibrosis. However, CVS does not test for neural tube defects. CVS can also be used for paternity testing.
CVS is recommended for women who:
- Have a family history of birth defects
- Are 35 years old or older
- Have a previous child with a birth defect
CVS is not recommended for women who:
- Have an active infection (STD)
- Have vaginal bleeding
- Have severe bending of the uterus
- Are carrying twins
There are two ways a physician can remove chorionic villi cells:
- Transcervical (TC) CVS
- Transabdominal (TA) CVS
In TC CVS, the physician guides a thin catheter through the vagina and cervix and into the placenta where a small amount of tissue is obtained. Ultrasound is used to help guide the physician and decrease risk to the fetus.
In TA CVS, the physician guides a needle from the abdomen and into the placenta where a small amount of tissue is obtained. A local anesthetic may be used. The process is similar to amniocentesis. Just as with TC CVS, ultrasound is used to help guide the physician and decrease risk to the fetus.
After the procedure, you should plan to rest and refrain from intercourse and strenuous activity for the remainder of the day. You may experience cramping or pain and light spotting of blood. Call your healthcare provider is you experience fever, chills, or leaking amniotic fluid.
If you are carrying more than one fetus, the physician will take a sample from each placenta. This can be done using a combination of TA CVS and TC CVS. However, CVS is not recommended with twins.
Preliminary results may be available within two to four days, but may not be accurate. Final results are available about seven to 10 days after the procedure. CVS is highly accurate (~98-99%).
The primary risk with CVS is miscarriage. The risk of miscarriage is 1 in 100. An infection as a result of CVS is rare. When CVS is performed before 9 weeks, an increased risk of fetal limb abnormalities has been reported.
CVS can cause a small amount of fetal blood to leak into your circulation. This can be a problem if the mother is Rh-negative. If you are Rh-negative, you should receive RH immunoglobulin after the procedure.
If CVS results indicate that there may be a problem, additional testing and counseling is recommended.
- Amniocentesis
- Blood and Urine Tests
- Group B Streptococcus (GBS) Screening
- Percutaneous Umbilical Blood Sampling (PUBS)
- Triple Screen or Triple Marker Test
- Ultrasound (Sonogram)
