Transabdominal chorionic villus sampling for rapid karyotyping in advanced gestation.

Late pregnancy fetal karyotyping is not employed often because a clinical decision about labor and delivery may be required before the results would be available. However, percutaneous umbilical blood sampling (PUBS) has been used recently to obtain fast karyotypes. We have extended our chorionic villus sampling (CVS) procedure to the second and third trimesters and compared the results obtained with late CVS and PUBS. CVS karyotypes were obtained faster and may be technically easier to perform.