Initially conceived as problem-focused programming events, hackathons have expanded to encompass a range of issue areas, stakeholders and activities. There have been important critiques of hackathons in relation to their format and structure, their epistemological assumptions, and their outputs and impacts. Scholars working in Feminist HCI have proposed design considerations for more inclusive hackathons that focus on social justice outcomes for marginalized groups. Evaluative work on hackathons has assessed entrepreneurial contributions, skill development, and affective impacts, but largely absent from the analysis is a view of longterm personal impacts on participants. What kinds of lasting impacts (if any) do issue-focused hackathons have on participants themselves? In this paper, we describe a post-hoc qualitative study with participants and organizers of a postpartum health hackathon in the U.S., one year after the event took place. Our goals were to understand people's motivations for participating, what impact (if any) their participation had on their lives, and how (if at all) their participation shaped how they now understand postpartum health. Our findings indicate that the hackathon functioned as a space of "feminist consciousness raising" in that it provided space for navigating and sharing personal experiences, contextualizing and connecting those experiences to structural oppression, and developing participants' self-and collective-efficacy to create design interventions and enact social change. Feminist consciousness raising is not just "awareness-raising", but rather a specific historic and contemporary practice which we describe and situate in relation to personal experiences of oppression around stigmatized topics. With these findings, we situate feminist consciousness raising in relation to the literature on hackathons and Feminist HCI, speculate which aspects of the design of the event led to it fostering feminist consciousness raising, and generate recommendations for how to intentionally bring feminist consciousness raising to the design of hackathons and innovation events. CCS Concepts: • Human-centered computing → Participatory design; • Social and professional topics → Race and ethnicity; Gender.