Socially Embedded Digital Coaching Platform to Promote Healthy Lifestyle and Mental Health in Underprivileged (Pre)Pregnant Couples and Young Families (Our Smart Family Buddy Program): Protocol for a Mixed Methods Study.

Background: The early life course, that is, from preconception up until the first 1000 days of life, is pivotal for optimizing parental and child health. In deprived settings, unfavorable lifestyle behaviors and poor mental health are more prevalent, while access to effective, context-sensitive support is limited. Digital interventions combined with community-based approaches may help address these disparities. Objective: This protocol describes the methodology and initial progress of the Our Smart Family Buddy (OSFB) program, which aims to develop, implement, and evaluate a socially embedded digital coaching platform to improve nutrition and mental well-being among (pre)pregnant couples and families in deprived neighborhoods. Methods: The OSFB program is a multiphase mixed methods program conducted within a transdisciplinary consortium consisting of 6 interrelated work packages. The program is structured in 3 phases: phase 1, exploration and preparation; phase 2, cocreation, design, and development; and phase 3, prototype evaluation and optimization. Data collection includes quantitative questionnaires, qualitative interviews and focus groups, and digital user data from the platform. The primary outcomes include lifestyle behaviors (nutrition and sleep), mental well-being, user engagement, and implementation outcomes, including feasibility, acceptability, and reach. Results: The program was funded in 2022. A transdisciplinary consortium was established in 2023. Data collection and analysis for phase 1 were conducted between 2023 and 2025, including literature reviews and exploratory interviews. A deprived neighborhood in the municipality of Rotterdam, the Netherlands, was selected as the target neighborhood. The target population was defined as (pre)pregnant couples and families with a child aged <4 years. Phase 2 is ongoing (2024-2026), focusing on iterative design through locally established field labs and community building. Phase 3 is planned for 2026 to 2028. Conclusions: This protocol describes a socially embedded, multiphase approach to developing and implementing a digital coaching intervention for families in vulnerable circumstances. Through a transdisciplinary approach within a real-world, local community setting, the OSFB program aims to develop a context-sensitive intervention to support sustainable behavior change in early life.