PROJECT SUMMARY/ABSTRACT Childhood maltreatment constitutes a grave public health crisis associated with devastating lifelong costs, including heightened risk for psychopathology1,2 and substance use,3 poorer socioemotional functioning,4,5 impaired cognitive functioning,6,7 lower educational attainment,8 and physical health problems9 such as heart disease,10 obesity,11 and even early death.12 Crucially, the deleterious costs of childhood maltreatment are not limited to those directly affected, but can also spillover into future generations via disrupted parenting and caregiving practices.13 Thus, identification of intervening mechanisms that may explain associations between maltreatment histories and parenting in the next generation can inform theory in this area of research and illuminate meaningful points of intervention in clinical practice. The long-term objective of the proposed project is to examine multisystem physiological stress reactivity indicators as mediators of associations between maternal maltreatment histories and parenting during the perinatal period. The novelty of this project is twofold. First, this project will examine both Hypothalamic-Pituitary-Adrenal reactivity (Aim 1) and Parasympathetic Nervous System reactivity (Aim 2) as intervening links between maltreatment and parenting during a key developmental period. This is the first study to examine more than one physiological mediator of this association concurrently, as well as the first study to examine parasympathetic reactivity specifically. Second, informed by a Domain-Specific Approach14 to parenting, this project provides much-needed specificity in differential associations between physiology and parenting outcomes across the protection and reciprocity domains. This work addresses limitations of prior research by leveraging an existing prospective, longitudinal, study (n=85) of diverse, low-income women. The applicant’s dedicated mentorship team of expert investigators will foster the applicant's development in this important research area. Finally, the award and completion of this project will substantially aid in providing strong research training to a promising young scientist in developmental psychopathology, intergenerational transmission processes, and human physiology through quality mentoring and training opportunities for advanced research skills and enhanced interdisciplinary knowledge in relevant content areas. Moreover, the proposed translational research is highly novel and will contribute to knowledge of biopsychosocial parenting processes in the perinatal period, particularly among high-risk mothers.