How could chorionic villi sampling determine whether a fetus has genetic abnormalities?

CVS. Chorionic villus sampling is a procedure to obtain a small amount of tissue from the placenta. The placenta has the same genetic endowment as the fetus. So chromosomal or genetic testing of the chorionic villus will tell about the fetus.

Related Questions

Does chorionic villi sampling determine whether a fetus has genetic abnormalities?

Yes and no. Chorionic villi sampling is a procedure where a small sample of cells from the placenta are removed, early in a pregnancy. A lab can determine if there are any extra or missing chromosomes, or large parts of a chromosome that are extra or missing. Other tests on chorionic villi can look for abnormalities in single genes, but no test can determine that a baby has no genetic abnormalities.

How would chorionic villi sampling determine whether a fetus has genetic abnormalities?

Laboratory testing. Cvs sampling after 10 weeks of gestation can obtain tissue for testing. The tests usually done are chromosomal analysis or mutational analysis of a specific gene.
Karyotype. CVS is like having an amniocentesis only done earlier and with material directly obtained from the placenta. The material is tested for chromosomal abnormalities and may be subjected to more specific testing if there is a known genetic disorder in the family. It carries a slightly higher risk of miscarriage than amniocentesis. CVS will not detect neural tube defects (i.e. spina bifida)