Chorionic villus sampling (biopsy of the placental tissue) is usually performed in the 12th - 14th week of pregnancy. During this procedure, cells from the placenta are removed transabdominally with a fine needle; ultrasound is used the whole time to visualize the procedure. As with amniocentesis, the procedure usually lasts about 1 minute.
The results of chromosomal analysis are available after 1-2 days (short-term culture) or after 8-10 days (long-term culture). In special cases, additional tests may be performed for inherited diseases, such as metabolic disturbances. In rare cases, findings may be unclear, thus necessitating further tests to be carried out.
The risk of miscarriage after chorionic villus sampling is approximately the same as for amniocentesis. We recommend that patients go for a check-up examination with their regular gynecologist 1-2 days after the procedure, and that they avoid strenuous physical activity for a few days.