Background <p>Extremely preterm birth increases the risk of neurodevelopmental impairments. Early interventions supporting child and parent may improve child neurodevelopment, but evidence is limited. We aimed to evaluate the effect of the Stockholm Preterm Interaction-Based Intervention on neurodevelopmental outcomes at 24 months’ corrected age. Risk of autism spectrum disorder was examined as separate outcome. We also investigated whether the effect varied according to biological and psychosocial factors including maternal depressive symptoms.</p> Methods <p>This randomised controlled trial included 130 infants born extremely preterm. Participants were randomised to receive either the intervention in addition to an extended follow-up program (intervention group) or solely the extended follow-up program (control group). Neurodevelopment was assessed at 24 months' corrected age using the&#xa0;Bayley Scales of Infant and Toddler Development 3^rd edition.</p> Results <p>No significant group differences were found in cognitive, language, or motor development, neither in the overall group nor within the sub-group of children at risk of autism spectrum disorder. No interaction effects by biological and psychosocial factors were observed.</p> Conclusion <p>Neurodevelopmental effects of the intervention were not observed at 24 months' corrected age in our cohort of children born extremely preterm. Follow-up is important to evaluate long-term effects.</p> Impact statement <p><UnorderedList Mark="Bullet"> <ItemContent> <p>A strength-based, post-discharge parent-infant intervention showed no short-term effects on neurodevelopment at 24 months' corrected age in children born extremely preterm.</p> </ItemContent> <ItemContent> <p>This trial contributes to the limited evidence on early, family-centered interventions after extremely preterm birth, indicating that measurable benefits may require longer follow-up or higher intervention intensity.</p> </ItemContent> <ItemContent> <p>Our findings emphasize the importance of continued longitudinal evaluation and refinement of early support programs to better promote both child development and parental well-being.</p> </ItemContent> <ItemContent> <p>Around 44% of the children scored below -1 SD indicating risk in cognitive, language or motor development, highlighting the need for interventions and continuous follow-up.</p> </ItemContent> </UnorderedList></p>