Traumatic birth experience (TBE) is an underappreciated risk for postpartum post-traumatic stress disorder (p-PTSD), depression and anxiety, which contribute to significant social, medical, and economic burden. Both TBE and postpartum psychopathology are disproportionately experienced by underserved and minoritized populations, further widening the known gap in maternal health outcomes. We urgently need innovative, wholistic, strengths-based approaches to care for pregnant people with clear mechanisms of impact. Dispositional optimism (DO) is a resilience factor by which we can move the needle on maternal health, and has been associated with wide-ranging mental health benefits, including prevention and treatment of PTSD in non-pregnant populations. Mindfulness interventions show promise in improving DO and thus may be a transdiagnostic approach to bolstering resilience and positively impact health and health equity. However, this approach has not been utilized in a perinatal population. In this project, we propose a randomized clinical trial comparing use of an existing, equity-focused, perinatal mindfulness phone application (Expectful) to routine care for pregnant individuals with low DO. 100 participants will be randomized in order to assess 1) feasibility and acceptability of the digital mindfulness intervention, 2) impact of Expectful on DO, TBE and p-PTSD, and 3) explore perspectives on the role of optimism and other resilience mechanisms in pregnancy experience and outcomes. Results from this trial will support a planned type II hybrid implementation-effectiveness randomized trial to reduce TBE and p-PTSD, and reduce health disparities via improvements in DO.