Chorionic villus sampling followed by amniocentesis in the same pregnancy.

In our consecutive series of 2,574 chorionic villus sampling (CVS) patients, 146 women (5.7%) underwent a subsequent amniocentesis in the same pregnancy for the indications of absent or insufficient villi (3.3%), elevated maternal serum alpha-fetoprotein (0.93%), CVS mosaicism (0.89%), culture failure (0.23%), specimen contamination (0.15%), and CVS aneuploidy (0.12%). Patients presenting for a CVS should be informed of the possible need for a subsequent amniocentesis in the same pregnancy. There is a need for individual prenatal diagnosis programs to analyze their own data and provide genetic counseling information which pertains specifically to their institution.