Chorionic villus sampling (CVS) is a test done during early
pregnancy that can find certain problems with an unborn baby (fetus). It may be
done when either parent has a family history of an inherited genetic disorder
or when the mother wants to find out her chances of having a baby with a
Chorionic villi are tiny finger-shaped
projections found in the placenta. The genetic material in chorionic villus
cells is the same as in fetal cells. During CVS, a sample of chorionic villus
cells is taken and examined for chromosome problems, such as Down syndrome. The
sample is usually collected by putting a thin flexible tube (catheter) through
the vagina and cervix into the placenta (transcervical CVS). The sample can
also be collected by putting a long, thin needle through the belly into the
placenta (transabdominal CVS). Ultrasound is used to guide the catheter or
needle into the correct position for collecting the sample.
usually done late in the first trimester, between the 10th and 12th weeks of
Sarah Marshall, MD - Family Medicine & Siobhan M. Dolan, MD, MPH - Reproductive Genetics
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