Purpose Consumer engagement within co-design research and service-delivery contexts is increasing internationally. Despite growing expectations for consumer involvement in funded research, empirical evidence describing meaningful co-design from mothers’ perspectives remains limited. This case study explored mothers’ experiences of participating in co-design for a perinatal mental health research project. Methods The case study involved two 90-minute online workshops with four mothers at the conclusion of a 14-month co-design research project. Workshop 1 data were analysed using a participatory sensemaking within a qualitative descriptive framework. Workshop 2 involved collaborative refinement and consensus of preliminary interpretations. Results Six interconnected learnings informed a conceptual model of meaningful co-design. The model identified: (i) skilled facilitation as underpinning the key principles; (ii) co-design as a relational experience rather than a procedural process; (iii) flexibility as enabling equitable participation over time; (iv) clear researcher–participant boundaries as enhancing trust; (v) iterative checking of assumptions as essential; and (vi) positive consumer experiences as promoting ongoing advocacy for consumer engagement. Conclusion Meaningful co-design was experienced as an active, relational and facilitation-dependent process rather than a procedural requirement. These findings provide practice-based guidance and offer a conceptual framework for understanding how meaningful consumer co-design engagement is experienced by mothers, strengthening methodological transparency in participatory perinatal mental health research.
