The Playful Learning in Infancy Program (PLIP): Protocol for an efficacy study of a universal intervention promoting parents’ playful interaction with their infants aged 0-1 year

Objective Early parent–infant interactions, particularly warm, responsive, and mutually enjoyable engagement, are important factors promoting the mental health and wellbeing of young children. Playful interactions are not only related to motor and cognitive development but also work as a relational process central to child socio-emotional development and resilience. This study evaluates the efficacy of a newly developed universal intervention “The Playful Learning in Infancy Program” (PLIP) compared to Care As Usual (CAU) in the primary care context of the national Home-visiting Program. PLIP aims to promote playful parent-infant interactions during the first year of life. Methods PLIP is delivered by 28 health visitors from two municipalities. Approximately 2,128 parents will be invited to participate in the control group, and 2,526 parents will be invited to participate in the intervention group. The study uses as a quasi-experimental cohort study design with data obtained at five timepoints comparing a control group receiving CAU and the intervention group receiving PLIP in addition to CAU. The primary outcome is frequency of parent-infant playful interactions. Secondary outcomes include parental attitudes towards play and infant socioemotional development. The project is registered at ClinicalTrials.gov. Conclusion The study evaluates the efficacy of a newly developed intervention, PLIP in promoting parent-infant playful interactions and how it relates to early socioemotional development of the child. This knowledge may guide future interventions aiming to promote child mental health through play-based interventions.