STUDY OBJECTIVE: To examine the effectiveness of an education intervention on emergency physician accuracy in identifying pregnancy-related findings from first-trimester point-of-care ultrasound. Case features associated with the odds of a correct response were also determined. METHODS: This was a multicenter prospective cross-sectional study in a convenience sample of emergency physicians in the United States and Canada. The unsupervised web-based education intervention included first-trimester point-of-care ultrasound cases acquired through the transabdominal (n=200 cases) or transvaginal (n=200 cases) approach. Physicians deliberately practiced identifying pregnancy-related imaging findings until they achieved a mastery standard. RESULTS: In 204 participants, there were learning gains in accuracy (15.2%
95% confidence interval [CI] 14.6 to 15.8), sensitivity (15.1%
95% CI 14.3 to 15.9), and specificity (14.3%
95% CI 13.7 to 15.0). Of these, 132 (64.7%) achieved the mastery standard in a median of 60 cases (interquartile range 58 to 83). Case features associated with an increased odds of a correct intrauterine pregnancy "present" diagnosis were transvaginal versus transabdominal-acquired images (odds ratio [OR]=1.5
95% CI 1.3 to 1.8) and fetal heartbeat (OR=4.3
95% CI 3.4 to 5.5). A decreased odds was associated with an eccentrically located intrauterine pregnancy (OR=0.2
95% CI 0.1 to 0.2), subchorionic hemorrhage (OR=0.5
95% CI 0.4 to 0.6), adnexal mass (OR=0.7
95% CI 0.6 to 0.9), and endometrial collection (OR=0.1
95% CI 0.09 to 0.2). CONCLUSIONS: This study's intervention was effective in teaching first-trimester point-of-care ultrasound image interpretation and identified the specific variables that posed the greatest diagnostic challenges. The methods and results from this work can serve to expand learning opportunities for this critical skill in emergency medicine.