by A.L.Smith

Created on: January 07, 2010

Chorionic villus sampling or CVS is a method used to diagnose abnormalities in a fetus. CVS is most always performed during the first three months of pregnancy, it can be performed as early as ten weeks gestation. Although normally done early, it is possible to have it done later on.

Chorionic villus sampling is used to determine if a child will be born with a chromosomal disorder, like

Down's syndrome, or a genetic disease. CVS is done on pregnant women who have a family history of genetic disease or are at high risk of having a child with a chromosomal disorder.

Chorionic villus sampling takes about thirty minutes to complete and is done on an out patient bases. CVS can be performed with or without sedation depending on the method used. Which type of method to use largely depends on the place where the placenta is attached to the uterus.The most common CVS test is done vaginally. A hollow tube called a Canula, with a syringe attached, is inserted in the vagina and then passed up into the uterus. The syringe then sucks a small amount of chorionic villi from the placenta. These villi are genetically identical to the fetus. CVS may also be done by inserting a needle into the uterus through the abdominal wall. The villi are then withdrawn through the needle. Both methods of extracting the villi are done with the aid of an ultrasound to guide both the physician and the instrument.

Chorionic villus sampling, like most procedures, carries some side effects and risks. The biggest risk being miscarriage. The odds vary to some degree, anywhere from one in one hundred to one in four hundred. Leaking of Amniotic fluid after CVS is also a risk because low levels of Amniotic fluid can be dangerous to the fetus. During CVS a small amount of fetal blood can enter the blood stream, if you have an Rh negative blood type this can cause complications, make sure you discuss this with your physician. Some other possible side effects include, cramping, and mild pain. Light spotting is another side effect, however if bleeding is as heavy as a normal menstrual period contact your doctor.

CVS is not a test to enter into lightly. Ask your doctor about the possible side effects and risk factors. Be aware that Chorionic villus sampling can produce false positives which will then require further testing before any important decisions are made.

Sources:

  wisegeek.com

 uptodate.com

Canadian Home Medical Encyclopedia

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