Anomaly Detection With an Expanded Standardized First-Trimester Fetal Anatomic Ultrasound Screening Protocol

To evaluate the clinical utility of a novel comprehensive StaFFAUS (standardized first-trimester fetal anatomic ultrasound screening) protocol.

This retrospective single-center study included pregnant patients undergoing first-trimester ultrasound screening at 11 6/7-13 6/7 weeks of gestation between 2013 and 2024. Identification of gold-standard-confirmed anomalies was assessed retrospectively according to an expanded first-trimester screening protocol with 30 imaging planes called StaFFAUS, the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) Minimum-Requirement, and the ISUOG Detailed protocols. Diagnostic performance was evaluated in a subset validation cohort made up of all fetuses with structural abnormalities and a control group without structural abnormalities, selected at a 1:3 ratio. Examination time was assessed in 100 randomly selected scans. Pairwise DeLong comparisons were used to compare the area under the receiver operating characteristic curve (AUROC) between groups.

A total of 18,250 women carrying 19,417 fetuses were considered for inclusion. First-trimester screening identified 246 fetuses with structural abnormalities, comprising 580 individual detected anomalies (3.0%). Using 694 gold-standard-confirmed anomalies as the reference standard, StaFFAUS achieved a significantly higher anomaly-level detection rate than the ISUOG Detailed protocol (83.6% vs 67.3%, P<.001) and the ISUOG Minimum-Requirement protocol (83.6% vs 47.7%, P<.001). In the diagnostic performance cohort of 326 fetuses with anomalies and 978 fetuses in a matched control group (N=1,304), StaFFAUS showed the highest sensitivity (75.5%), accuracy (90.8%), and AUROC (0.857, 95% CI, 0.830-0.884), whereas the ISUOG Minimum-Requirement protocol achieved the highest specificity (99.0%). The AUROC of StaFFAUS was significantly higher than those of both the ISUOG Detailed (AUROC 0.820, P<.001) and ISUOG Minimum-Requirement (AUROC 0.769, P<.001) protocols. Median examination time was 28 minutes (interquartile range 22-35.5 minutes).

Compared with current ISUOG first-trimester screening protocols, StaFFAUS demonstrated superior anomaly detection and diagnostic performance. As an expanded standardized screening framework incorporating additional first-trimester anatomic views, it improves early detection of fetal structural abnormalities while remaining clinically feasible.