RESUMEN
OBJECTIVES: To compare first-trimester scan results between audited (AS), according to the Fetal Medicine Foundation criteria, and non-audited sonographers (NAS). MATERIAL AND METHODS: Retrospective observational study of N = 629 and N = 1290 NT and CRL measurements done by AS and NAS, respectively. RESULTS: For similar examined populations (similar CRL and maternal age at examination) NT values were significantly lower in NAS with NT of 1.0 mm or less in 26.9% of measurements taken by NAS (vs. 0.3% in AS). NT differed significantly between NAS and AS in all maternal age groups, except for patients below 24 years of age and in all CRL categories. CONCLUSIONS: Training of sonographic skills in fetal medicine needs to be complemented by a regular audit to ensure adequate quality of the measurements.