Project Summary/Abstract: Project 2 Almost 1 in 3 births in the United States involves cesarean delivery. A lifesaving intervention when appropriate, cesarean is associated with significant risks that include severe postpartum hemorrhage and severe maternal morbidity (SMM). Compared to vaginal delivery, women undergoing cesarean delivery incur the highest risk of postpartum hemorrhage and hemorrhage-related morbidity. In the last 30 years, significant disparities in rates of cesarean birth have developed for Black women, disparities that elevate their risks of morbidity from hemorrhage and mortality. Reducing cesarean rates is therefore essential for reducing postpartum hemorrhage and postpartum-related SMM. Eliminating disparities in cesarean delivery requires multifaceted, multilevel interventions that can be deployed at scale. We will build on our expertise in achieving population-level improvements in maternal outcomes (including hemorrhage and cesarean delivery) and long-standing collaborative partnerships with patients, communities, and public health agencies to identify and implement strategies to reduce disparities in cesarean birth and hemorrhage. Our state-wide quality improvement network with a sophisticated real-time data center will enable us to support complex equity interventions and track improvement. Capitalizing on our collaborative network of 218 hospitals covering 99% of births in CA, we will realize the following Specific Aims: (1) Use mixed method approaches to identify strategies to reduce disparities in rates of cesarean birth and cesarean-associated hemorrhages. (2) Center patient voices in the validation and continuous curation of action tools and resources that will be integrated into a Maternal Equity Guide, a toolkit of resources to drive equity change within hospitals. (3) Expand implementation of the Maternal Equity Guide in state-wide efforts to reduce disparities. (4) Assess effectiveness of the Maternal Equity Guide tools/resources and implementation strategies. We collect real-time patient-level data for all California births including patient-identified race and ethnicity allowing us to measure changes in multiple maternal health outcomes at state, hospital, and even provider levels. Combined with qualitative methods, this will provide a particularly robust analysis of effectiveness of our interventions. Results will establish a national roadmap for effectively integrating equity into large-scale quality improvement to address disparities in rates of cesarean births with potential application to other aspects of obstetric care.