Effects of Changes in Labor and Delivery Nursing Organizational Characteristics on Obstetric Outcomes and Disparities The rising rates of maternal morbidity and mortality in the United States demand answers. Childbirth is the most common reason for hospital care, comprising 1 in 9 hospitalizations. Maternal morbidities, including postpartum hemorrhage and peripartum infection, are principal determinants of maternal mortality. Cesarean delivery in low-risk women is associated with significantly higher maternal and infant morbidity. These three outcomes vary widely across hospitals and are marked by stark disparities between Black and non-Black women. There is a compelling need to examine factors in the health care system that account for these variations and disparities. Labor and delivery registered nurses are frontline care providers responsible for monitoring and early recognition of and intervention for the prevention of these outcomes. They provide continuous bedside care that is critical to achieving optimal birth outcomes. Evaluating the influence of nursing on obstetric outcomes, however, has been largely ignored. In other hospital populations, patient outcome variation has been linked to variation in nursing organizational characteristics, such as the nurse work environment, nurse workload, and the percentage of Bachelor of Science in Nursing (BSN) degree-prepared registered nurses. The clear clinical basis for nursing organizational characteristics to influence obstetric outcomes and disparities creates a critical need to investigate these relationships to inform professional guidelines and nursing unit organization to transform practice. We propose a novel, geographically representative, multi-hospital cross-sectional and longitudinal study. We will determine whether cross-sectional differences in nursing organizational characteristics (work environment, workload, BSN percentage), relate to differences in three obstetric outcomes and disparities in outcomes in 867 hospital observations from 2005, 2015, 2019, or 2023 in 26 states (Aim 1). We will study how longitudinal changes across time points, including “post”-pandemic, in nursing organizational characteristics influence changes in the three outcomes and disparities in these outcomes in a panel of 173 hospitals in 19 states (Aim 2). The Aim 2 panel comprises 309,670 deliveries per year. The study will capitalize on the availability of four national data sets, comprising nurse survey (National Database of Nursing Quality Indicators, RN4CAST) and patient data (Healthcare Cost and Utilization Project State Inpatient Data, state patient discharge data). This study addresses the NINR mission: “To solve pressing health challenges and inform practice and policy—optimizing health and advancing health equity into the future.” Our longitudinal and cross-sectional approaches along with broad geographic representation will provide actionable evidence for hospital administrators and professional ...