Parental psychological challenges and poor well-being are key factors in shaping both the quality of parent-child interactions and child development. Specifically, maternal psychological distress is a central determinant of child development. Elevated levels of distress in mothers are associated with poorer child cognitive, behavioural and social-emotional outcomes, with effects persisting into adolescence and adulthood. While this highlights the critical importance of early prevention and intervention efforts to support parents, postpartum mental healthcare remains limited, despite ongoing and evident needs.

This protocol outlines a 2-year longitudinal follow-up study investigating the impact of a secondary perinatal programme (ie, Toi, Moi, Bébé), completed by mothers during pregnancy, and its impact on children’s cognitive and social-emotional functioning at 24 and 48 months. Further, the study aims to explore whether maternal self-efficacy and emotion regulation may serve as potential mediators or moderators of the relationship between programme participation and child development outcomes. The research aims to leverage the Toi, Moi, Bébé programme, by recruiting mother-child dyads (n=250) in which the mothers participated in the programme during pregnancy. Mothers were randomly assigned to complete the parenting well-being intervention either independently or with added telephone support. Participants who consent will be invited to take part in a two-wave follow-up at 24 months (T1) and 48 months postpartum (T2). At both time points, mothers will complete demographic questionnaires and standardised measures assessing maternal well-being (Generalised Anxiety Disorder-7, Edinburgh Postnatal Depression Scale and Perceived Stress Scale), child cognitive functioning (Ages and Stages Questionnaire-3 and MacArthur-Bates Communicative Development Inventory), child social-emotional functioning (Ages and Stages Questionnaire, Social Emotional—second Edition-2 and Child Behaviour Checklist for Ages 1.5–5), maternal emotion regulation (Cognitive Emotion Regulation Questionnaire) and maternal self-efficacy (Parental Cognitions and Conduct Towards the Infant Scale & Me as a Parent Scale). Parents’ perceptions of their parenting experience will be measured using the Parental Reflective Functioning Questionnaire. Mother-child interaction, parenting quality and cognitive stimulation in the home environment will be measured using a brief virtual interview (StimQ₂-Toddler) and a naturalistic observation assessment (Parenting Interactions with Children: Checklist of Observations Linked to Outcomes). Using RStudio, linear mixed models will be used to assess the impact of the intervention (online intervention only vs only with telephone support) on child cognitive and social-emotional development at T1 and T2. In parallel, separate models will be conducted to examine associations between maternal emotion regulation and self-efficacy on the child development outcomes at the same timepoints. Exploratory analyses will be conducted to examine potential moderating effects of child sex and group assignment on the associations between maternal emotion regulation and self-efficacy and child developmental (cognitive and socioemotional) outcomes, using causal inference models.

The current study has been registered, reviewed and approved (MP-37-2025-10894) by the Research Institute of the McGill University Health Centre Research Ethics Board. Findings from this research will be disseminated through peer-reviewed open access publications, and presentations at national and international conferences.

NCT05110456.