ABSTRACT Pregnant or postpartum people experiencing incarceration (PPEI) represent a critical U3 population that is understudied due to barriers within carceral institutions, underrepresented due to the exclusion of institutionalized individuals from research, and underreported because they comprise a minority within incarcerated people. PPEI have higher than average representation of NIH-designated health disparities, and disparities in the fulfillment of desired postpartum sterilization are particularly complex for PPEI because of the unique multilevel barriers that influence health outcomes. Tragically, many PPEI have been sterilized without consent. Thus, policies and laws are in place to limit access of PPEI to sterilization given the challenges involved in obtaining true informed consent, potential of coercion, and risk of regret after incarceration. However, others with well-formulated, long-standing desires to obtain postpartum sterilization have encountered barriers over several domains, including harsh built environments, punitive sociocultural environments, and health care systems. Therefore, nuanced consideration is required to balance these protections with the unintended consequence of disparities. Investigation of factors that influence postpartum sterilization desire and fulfillment in PPEI represents a critical knowledge gap. In this Administrative Supplement, we seek to extend efforts from our parent R01 (1R01HD098127H) to meet an overall objective of better understanding the goals, experiences, and health outcomes of PPEI desiring postpartum sterilization and their delivering medical team. This objective is directly related to Strategic Goal 1.3 of the ORWH and directly responsive to the NOSI’s specific areas of research interest in terms of assessing structural determinants of health, utilizing preventive health care and exploring the intersectional stigma impacting this U3 population through a multidimensional research framework. Leveraging our extensive expertise in bioethics and observational analysis and long-term collaboration with the North Carolina state prison system, we have the infrastructure to rapidly meet our objective. Consistently, our Aims are to 1) Longitudinally assess the contraceptive goals of PPEI by retrospectively abstracting medical record data from pregnant women who were incarcerated from 2016-2021 (n=850) to understand postpartum sterilization decision-making and compare with the general population via a similar dataset created through the parent grant. 2) Identify the attitudes, beliefs, and practices of PPEI and their obstetricians regarding postpartum sterilization by performing and analyzing semi-structured interviews of PPEI requesting postpartum sterilization and their delivering obstetrician (n=15 dyads); 3) Develop clinical guidance for ethical postpartum sterilization for PPEI by performing robust ethical analysis from a patient-centered and health-equity lens. Our results will provide a cri...