Chorionic villus sampling: experience with 3016 cases performed by a single operator.

Abstract

To describe our experience with 3016 first-trimester chorionic villus sampling (CVS) procedures, all performed by a single operator, to assess the influence of operator experience on the safety and efficacy of CVS. Transcervical or transabdominal CVS procedures were performed on 3016 patients between the gestational ages of 9-12 weeks. The sampling success rate, procedure complications, cytogenetic results, and pregnancy outcomes were tabulated and analyzed. Samples adequate for diagnosis were obtained in 99.7% of the cases. The mean (+/- standard deviation) number of insertions per procedure was 1.1 +/- 0.4. The percentage of procedures in which the sample was obtained with a single insertion increased from 51% in the first 100 cases to 96% in the last 2516 cases. There were 56 (1.94%) first- and second-trimester pregnancy losses among 2892 pregnancies intended to continue. This loss rate compares with published baseline risk figures for miscarriage of approximately 2-3%. No difference in pregnancy loss rate followed one or two catheter or needle insertions, but the need for three insertions was associated with a significantly increased loss rate (6.7 versus 1.9%; chi 2 = 4.35, P < .05). Operator experience plays a significant role in the safety and efficacy of CVS.