Hospital Variations in Postpartum Care Access, Quality, and Outcome: The Intersectionality of Residence Location and Race/Ethnicity Summary The United States (U.S.) is amid a maternal health crisis, with increasing postpartum readmissions (PPR) and maternal mental and substance use disorders. Rural and racial disparities in these postpartum care and health outcomes especially persistent in the Southern U.S.. Most importantly, South Carolina (SC) ranked top 7th for the highest maternal mortality rate in the U.S.. In such a rural state where nearly 30% of reproductive- age women were Black population and where racial inequities in adverse maternal outcomes have been unacceptably persistent, the need to improving postpartum health outcomes is acute. Yet, addressing the increase in PPR requires a localized holistic approach that encompasses improved preconception, antenatal, and perinatal care to reduce healthcare disparities. Our primary goal is to quantify hospital variations in postpartum health and health care inequities in racial underrepresented and rural postpartum women. We will analyze >300,000 childbirths in SC from 2018-2023 by leveraging statewide population-based vital records and hospital-based inpatient, outpatient, and emergency department records from preconception, pregnancy, through 12 months postpartum. These data will also be linked to hospital surveys for a variety of hospital factors. The aims of our study are to: Aim 1: Investigate the intersections of residential rurality and race/ethnicity on the postpartum care access, quality, and outcomes throughout 1-year post-birth. Aim 2: Examine the roles of hospital attributes (obstetric patient race/ethnicity mix, perinatal care level [Level I-IV], obstetric workforce models [obstetricians, family physicians, and/or nurse midwives], annual delivery volume) play on health inequities in postpartum outcomes. The proposed research is significant by identifying hospital factors for postpartum inequities, to inform targeted sustainable practice and policies for the improvement of maternal health and elimination of rural and racial/ethnic inequities at hospital maternity care settings. It builds on our multidisciplinary research team from U01HD110062 and 3R01AI127203-05S2 with extensive experience in 1) rurality and race/ethnicity, 2) social and structural determinants of health, 3) perinatal care equity, 4) mental health and substance use disorder, and 5) health behaviors. This research is innovative in leveraging population-based all-payer healthcare records-vital statistics linkage data that captures underrepresented and underserved perinatal populations that were often underreported in health care claims data from preconception, pregnancy, intrapartum, through 12-month postpartum, allowing us to identify postpartum inequities resulting from different perinatal periods. Considering striking racial disparities in postpartum outcomes, racially diverse population, and historical systemic r...