Oral Plenary Session 1

Objective: Mental health conditions are among the most common perinatal complications and contribute significantly to maternal morbidity and mortality in the US.Access to timely, effective mental health care remains limited.We aimed to evaluate whether Baby2Home (B2H), a collaborative care modelbased digital health intervention co-designed with new parents, improves mental health, relationship health, and self-efficacy outcomes over the first year postpartum. Study Design:We conducted a randomized controlled trial of B2H vs. usual care among postpartum primiparas with term infants recruited from two large birthing hospitals.B2H is a digital health tool that includes infant care trackers designed to boost parenting confidence and communication, individualized anticipatory education, mental health selfmanagement tools, and a care manager for on-demand mental health and problem-solving support.Patient-reported outcomes, including stress (PSS), depression (PHQ9), anxiety (GAD7), global health (PROMIS-GH), relationship satisfaction (RDAS), and self-efficacy (PROMIS-SE), were collected electronically at 1, 2, 4, 6, and 12 months postpartum.Analyses followed intention-to-treat principles and used linear mixed-effects models to estimate between-group differences over time.Results: A total of 642 postpartum people were randomized.Compared to usual care (n = 321), participants randomized to B2H (n = 321) reported significantly fewer symptoms of stress (β -4.05, 95% CI -4.99, -3.11), depression (β -1.42, 95% CI -1.94, -0.89), and anxiety (β -0.92, 95% CI -1.52, -0.33) (Figure).They also reported better global health (β 2.69, 95% CI 1.19, 4.19), higher relationship satisfaction (β 2.20, 95% CI 1.03, 3.36), and greater self-efficacy (β 1.31, 95% CI 0.29, 2.33).Conclusion: B2H led to significant and sustained improvements in mental health, relationship health, and self-efficacy over the full first year postpartum.These findings underscore the public health potential of scalable, evidence-based digital tools to address rising rates of perinatal mental health conditions and to improve outcomes for new families.