PROJECT SUMMARY/ABSTRACT Maternal morbidity and mortality rates are increasing in the United States (US), and extreme racial and geographic disparities persist, despite these outcomes being largely preventable with timely and appropriate care. Most medical responders are not optimally proficient in caring for patients who experience maternal medical emergencies, including maternal cardiac arrest. This gap exists among first responders and across medical specialties, and even for OB-specialists trained in Advanced Cardiovascular Life Support. Leading organizations in women’s health care and resuscitation have all called for efforts to better prepare healthcare workers (HCWs) for maternal medical emergencies, and increasingly federal agencies and state legislatures are incentivizing or requiring hospitals to provide this education and training. Nonetheless, the implementation of evidence-based education for maternal medical emergencies in health systems across the US is inconsistent and national credentialing standards do not exist. The study team developed Obstetric Life SupportTM (OBLSTM), the first of its kind interdisciplinary simulation curriculum to train HCWs across the chain of survival on preventing, recognizing, and managing maternal medical emergencies. Preliminary data from a randomized, cross-over trial shows significant improvement in clinical competencies, knowledge, and confidence for the intervention group compared to the control. However, as this validated simulation training is only just now available and accessible to providers and healthcare organizations, dissemination and implementation best practices do not yet exist. The objective of this project is to evaluate a train-the-trainer approach for implementing OBLSTM in a diversity of hospital and prehospital contexts throughout Arizona. The study will be conducted in partnership with the Arizona Perinatal Trust, the oldest regionalized perinatal healthcare system in the US, and Arizona Emergency Medical Services. A Steering Committee composed of local, regional, and national stakeholders will provide guidance and oversight for all study activities. Specifically, the study aims to: (1) Identify and train HCWs from hospital and prehospital contexts in Arizona to be OBLSTM instructors, prioritizing those that serve maternity care deserts and other marginalized communities at risk of adverse maternal health outcomes; (2) Implement OBLSTM in hospital and prehospital contexts across the state, with the training being led by local instructors; and (3) Evaluate OBLSTM implementation and process outcomes. The study design entails a mixed methods approach, informed by the Consolidated Framework for Implementation Research and the RE-AIM framework. To promote rapid learning, we will conduct two back-to-back OBLSTM instructor training, implementation, and evaluation cycles, whereby the second cycle will take into account feedback and lessons learned from the first. The study’s rigorous pr...