Chorionic Villi Sampling (CVS)
Between the tenth and twelfth week, a Chorionic Villi Sampling (CVS) procedure can be performed to obtain cells from the placenta that have the same genetic make-up as the fetus. These cells are analyzed for chromosomal disorders, such as is seen in Down syndrome, and gene abnormalities that cause metabolic disorders, such as Tay-Sachs and Cystic Fibrosis.
Although available to anyone, the usual indications for this procedure are if:
the pregnant woman is 35 years of age or older,
there is a strong family history of a specific genetic disorder, or
both parents possess a gene for an inherited disorder.
Risks associated with CVS:
There is a risk of miscarriage associated with the CVS procedure.
An infection may develop.
Limitations of CVS:
Not all genetic disorders can be detected. For certain genetic tests, there is greater reliability of results when testing individuals whose ethnicity puts them at a higher risk (because there is a higher than normal prevalence of specific genetic disorders in that ethnic group).
