Chorionic Villus Sampling – CVS
Chorionic Villus Sampling CVS is a prenatal test done on some pregnant women. This test is done to check for genetic problems and birth defects in the baby. This test may be done if you or your partner’s medical history reveals potential risk.
How is CVS performed ?
This test can be done through the cervix (transcervical) or through your belly (transabdominal). It involves the removal of some chorionic villi cells from the placenta at the point where it attaches to the uterine wall.
Transcervical : This is the most common method. During this procedure , a thin plastic tube passes through the vagina and cervix to reach the placenta. An ultrasound is used as guide. A small sample of chorionic villus tissue is then gently suctioned out.
Transabdominal : Using an ultrasound as a guide, a needle is inserted through the abdomen and uterus and into the placenta. A small sample of the tissue is drawn into the syringe. This procedure is similar to an amniocentesis. However the CVS collects larger samples and provides faster results.
What are some of the reasons for having a CVS ?
You may have a CVS performed if you are at higher risk of having a baby with genetic abnormalities. You are at high risk if you fall into the following category.
- age 35 and older
- have a previous child or pregnancy with birth defect
- family history of genetic disorders
- abnormal screening results
When is CVS performed ?
This test is performed between 10 and 13 weeks from your last menstrual period. The test may be chosen over an amniocentesis because it is performed earlier.
What does the test look out for ?
CVS detects chromosomal abnormalities such as Down syndrome and genetic disorders such as cystic fibrosis. It can also be used to access DNA for paternity testing before delivery. Unlike an amniocentesis, this test cannot be used to check for neural tube defects.
Are there any risks ?
Like any other test, There are risks involved. Some of the risk include the following :
What do the results mean ?
A normal result means the developing baby shows no signs of genetic defects.
An abnormal result may however be due to a many genetic abnormalities, some of which include :
- Down’s syndrome
- Tay-Sachs Disease
After an abnormal result, talk to your doctor about your options. Your baby may be able to be treated with medicines or even surgery before birth. There may also be treatment and surgery the baby can have after birth.
Choosing to do a CVS is an option. Your health care provider, genetic counselors and spiritual leasers can help you make this decision.Knowing the results also help you prepare emotionally and physically for taking care of a child with special needs.It is important to discuss the benefits and risks of the test with your physician.
Chorionic villus sampling. March of Dimes. http://www.marchofdimes.org/pregnancy/chorionic-villus-sampling.aspx. Accessed January 2, 2015
Chorionic villus sampling. National Library of Medicine. MedlinePlus. http://www.nlm.nih.gov/medlineplus/ency/article/003406.htm. Accessed January 2, 2015