Chorionic villus biopsy is a technique of taking chorionic villi from the placenta for prenatal genetic testing. The chorionic villi are biopsied through the vagina or abdomen. Chorionic villus analysis can diagnose chromosomal abnormalities such as Down syndrome as well as other genetic diseases. Chorionic villus biopsy is of great significance in prenatal diagnosis.

Triploidy is a rare chromosomal abnormality. While normal humans have 46 chromosomes (diploidy 2n=46), triploidy has 69 chromosomes (triploidy 3n=69) in all cells of the body.