RecruitingBehavioural interventionA Digital Intervention to Decrease Self-Stigma Among Pregnant and Postpartum Women With Substance Use DisorderDigital interventions have the potential to support healthier behaviors among pregnant and postpartum women (PPW) with substance use disorders (SUDs) and may also provide a promising method for reducing their self-stigma. Enhearten is a digital intervention designed to foster adherence to medications for addiction treatment (MAT) while considering the unique needs of PPW, but its effects on self-stigma, treatment retention, and SUD outcomes have not been rigorously tested. The investigators will conduct an individual-level multicenter randomized controlled trial to test the feasibility, acceptability, and efficacy of Enhearten on reducing self-stigma and on improving SUD treatment and recovery outcomes with a stigma-focused ecological momentary intervention (EMI) designed to: 1) screen for feelings of stigma and 2) counteract these vulnerabilities among PPW with SUD via just-in-time interventions.