Effectiveness of a longitudinal psychosocial intervention to strengthen mother–child interactions: The role of biological and contextual moderators

•Maternal interactive skills with 1-year-old child were assessed by observational measures.•The psychosocial intervention improved overall maternal interactive skills.•The intervention was more effective for vulnerable groups.•Gestational age and maternal schooling moderated the effects of the intervention.•The intervention was designed to be feasible in low-resource communities.