Performance of Transvaginal First-Trimester Anatomical Screening by Operators with Different Levels of Experience: A Randomized Controlled Trial

Background/Objectives: First-trimester anatomical screening (FTAS) enables early detection of fetal structural anomalies. However, data on transvaginal ultrasound performance across different operator experience levels remains limited. The primary objective was to compare the performance of transvaginal FTAS between inexperienced and experienced operators by comparing complete scan rates and anatomical visualization scores. The secondary objectives were to compare scan duration and learning curves between the two operators and to identify factors associated with successful examinations. Methods: In this randomized controlled trial, participants underwent transvaginal FTAS performed either by a first-year maternal–fetal medicine (MFM) fellow (inexperienced operator) or an MFM specialist (experienced operator) according to International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) guidelines. Complete scan rates, anatomical visualization scores, scan duration, factors affecting visualization, and learning curves were compared between groups. Results: A total of 139 participants were included in the analysis, with 70 and 69 examinations performed by the inexperienced and experienced operators, respectively. Complete scan rates and visualization scores were not significantly different between groups (41.4% vs. 44.9% and 86.4% vs. 91.2%, respectively). On multivariate analysis, operator experience was independently associated with higher visualization scores (p = 0.010), but not complete scan rates. Scan duration was similar between groups (median (IQR): 20 (17) vs. 20 (15) min; p = 0.211). Fetal presentation and uterine position significantly influenced visualization outcomes. The inexperienced operator demonstrated a trend of gradual improvement over time, though not significantly, whereas the experienced operator maintained stable performance throughout the study period. Conclusions: After training, no statistically significant differences were observed between less experienced and experienced operators with respect to complete scan rate, scan duration, and learning curve, although visualization score was significantly higher in the experienced examiner on multivariate analysis. However, our findings should be interpreted with caution, as the conclusions were based on the performance of only one examiner in each group.