Project Summary Abstract One in 20 pregnant women in the United States have clinically severe disordered eating (DE) symptoms during pregnancy, such as intentional vomiting, food restriction, and binge eating. DE during pregnancy is related to serious mental, emotional, and physical impairments, as well as pregnancy complications. Specifically, DE greatly increases the risk of miscarriage, hemorrhage, severe/prolonged vomiting, preterm birth, low birth weight, birth defects, impairments, and death, and doubles risk of severe anxiety and depression. DE disproportionally impacts women during reproductive years, and pregnant and postpartum women face unique challenges in this period, such as societal pressures (e.g., fear of gaining “too much” baby weight, pressure to lose weight quickly after pregnancy), along with pregnancy symptoms (e.g., difficulty eating, bodily changes, morning sickness). These vulnerabilities exacerbate DE, and risk of devastating health and pregnancy outcomes for mothers and infants. This proposal will modify our personalized self-guided system to identify treatment targets to ultimately address the unique presentation of the symptoms that drive DE in pregnant and postpartum women. There are currently no personalized digital self-guided interventions for this high-risk population. Thus, this supplement is to develop and modify a personalized, self- guided, digital intervention to address DE in pregnant and postpartum women. First, using idiographic models, we aim to identify the frequency of the most problematic symptoms that drive DE in this high-risk population (N=60). Second, we aim to modify and test if our digital therapeutic to address treatment targets personalized for pregnant and postpartum women reduces DE and increases their quality of life. Our highly novel methods are packaged within a digitalized program delivered directly to these high-risk women to intervene on the most problematic symptoms in a personalized manner within their day-to-day life, to improve access to care. This proposal is in-line with the parent grant, to provide the growth of our current mentorship training and research experiences for students, and support three early career researchers to be competitive for further independent funding. We aim to provide relevant and personalized DE interventions for pregnant and postpartum women, to reduce the risk for impairment and mortalities for both mother and infant.