Learning in medicine: chorionic villus sampling

Operator experience is considered to influence the safety and success of me dical procedures. We performed a retrospective survey to assess learning cu rves in chorionic villus sampling (CVS). Data of 2081 consecutive women, in whom CVS was carried out in a tertiary care university hospital for prenat al diagnosis, were available for analysis. Endpoints of the analysis were f etal loss, failure of the procedure and need for several needle insertions. Frequencies of each endpoint were calculated and plotted for consecutive s eries of 50 samplings per operator. Logistic regression analysis was used t o quantify the effect of operator experience. We observed a statistically s ignificant learning effect for the unit as a whole as assessed by fetal los s figures and the same tendency for need to do several insertions. We did n ot observe a (collective) learning effect for failure of the procedure. Ind ividual operators showed a significant learning profile for some endpoints. The individual learning profile predominantly depended on previous experie nce in amniocentesis. Our study substantiates the presence of a learning cu rve for CVS. This supports the view that centralization and restriction of CVS to a limited number of experienced operators within centres, is likely to have a positive influence on safety and success of the procedure. Copyri ght (C) 2000 John Wiley & Sons, Ltd.