This study examined the effects of simulation-based ultrasound training on the management of women with symptoms of pre-mature onset of labor. 12 midwives were randomized to simulation-based ultrasound training focusing on cervical assessment or no training (controls). The midwives in the intervention group were trained to an expert criterion on a high-fidelity transvaginal ultrasound simulator. Once this level was attained, they continued clinical training until proficiency in performing cervical scans independently. Proficiency was determined using a previously validated assessment instrument (the Objective Structured Assessment of Ultrasound Skills) and by sending in pictures for the Fetal Medicine Foundation certification programme.