MIDTRIMESTER AMNIOCENTESIS - INFLUENCE OF OPERATOR CASELOAD ON SAMPLING EFFICIENCY

OBJECTIVE: To evaluate the impact of operator caseload on the sampling efficiency for early and standard, mid-trimester amniocentesis. STUDY DESIGN: Prospective ascertainment of genetic amniocenteses performed during 36 months, grouped into early (23-14 weeks' gestation) and stan dard procedures (15-20 weeks' gestation). Details of each amniocentesi s were recorded immediately after sampling, and pregnancy outcomes wer e retrieved via questionnaires completed by the delivering physician. Sampling efficiency teas evaluated separately in the early and standar d cohorts in relation to operator caseload.RESULTS: In total, 193 and 707 patients underwent early and standard amniocentesis, respectively Forty of 46 physician-operators performed < 50 total procedures during the study interval (group A). When compared to operators performing g reater than or equal to 50 eases (group B, n = 6), a higher rate of si ngle-pass success was noted among group B physicians for both early an d standard procedures (1 vs. B, early: 40/45 vs. 145/148, P = .018; st andard: 243/295 vs. 384/412, P < .0001). Logistic regression confirmed an independent effect of physician caseload on sampling efficiency an d it significant interaction between physician caseload and simultaneo us ultrasound guidance in predicting single-attempt success. CONCLUSIO N: Operator caseload directly influenced sampling efficiency for both early and standard, midtrimester amniocentesis.