Background <p>Traumatic cardiac arrest (TCA) is a time-critical emergency with substantial heterogeneity across prehospital systems. Standardized reporting using Utstein-recommended variables is essential to enable valid comparison and synthesis across studies. To map how prehospital TCA studies published between 2020 and 2025 report Utstein-recommended variables, assess adherence to core and supplementary elements, and identify gaps and variation in reporting practice.</p> Methods <p>We conducted a scoping review following Joanna Briggs Institute guidance and reported according to PRISMA-ScR. PubMed, Embase, Scopus, and Web of Science were searched for English-language primary studies. Utstein-recommended variables were charted using a prespecified codebook and mapped to Utstein core and supplementary elements. Reporting completeness was summarized descriptively, and study-level reporting patterns were visualized using a heatmap and an UpSet plot.</p> Results <p>Fifty studies were included. Core elements were more consistently reported than supplementary elements (≥50% reported in 72.0% vs 12.0% of studies). Demographics and arrest etiology were almost universally reported (98–100%), whereas time-interval and dispatch-related variables were rarely reported, including time to first shock (0%), dispatch time variables (4.0%), and time to first CPR (2.0%).</p> Conclusions <p>Reporting of Utstein-recommended variables in contemporary prehospital TCA studies is incomplete and uneven, with persistent underreporting of dispatch- and time-interval elements and limited co-reporting of key core variables required for comparability. Improved adherence to a minimum Utstein-aligned dataset, augmented by trauma-specific descriptors, may strengthen standardization and interpretability of the TCA evidence base.</p> Clinical trial number <p>Not applicable.</p>