INCREASED RISK OF ANEUPLOIDY IN WOMEN HAVING UNSUCCESSFUL CHORIONIC VILLUS SAMPLING PROCEDURES

Objective To determine the incidence of fetal aneuploidy in women who had unsuccessful chorionic villus sampling (CVS) procedures. Design Re trospective study. Setting Pennsylvania Hospital, Philadelphia, Pennsy lvania, USA. Subjects Two thousand six hundred and sixty-eight women w ho underwent chorionic villus sampling, in 78 (2.9%) of whom villi cou ld not be obtained. Interventions Sixty-nine of 78 (88%) women who had an unsuccessful CVS procedure underwent a subsequent amniocentesis la ter in the same pregnancy. Main outcome measures The incidence of aneu ploidy identified from amniotic fluid chromosome analysis in the 69 wo men who had an unsuccessful CVS procedure compared to the frequency of aneuploidy in women having a successful CVS procedure. Results Of the 69 women who underwent a post-CVS amniocentesis because of failure to obtain chorionic villi, six aneuploid pregnancies were identified (8. 7%). The frequency of aneuploidy in the 2590 successfully sampled CVS patients was 2.5%. This difference was statistically significant (P = 0.009) by Fisher's exact test (two-tailed). Conclusions Women having a n unsuccessful CVS procedure should be informed that they may be at in creased risk for carrying an aneuploid fetus.