With chorion sampling, or chorionic villus sampling, placenta tissue (chorionic villus) is extracted from the abdominal wall and examined. The cells of the chorion contain the same chromosomes and genes as the growing child. With this method, some genetic illnesses can be recognized.
This test is an alternative to amniocentesis and is conducted with high-risk pregnancies between the 10th and 14th week of pregnancy. This is the case with pregnant women with a critical first trimester test result, or if there is genetic illness in the family. The test results are ready within a few days.
The risk of miscarriage due to chorion sampling is 1%. It remains unclear, however, whether the miscarriage in recorded instances at this early stage of the pregnancy might not have happened anyway.