In general, developmental course of newborns is hard to predict. Risk factors, such as brain lesions or atypical movements, assist prediction of neurodevelopmental disorders, including cerebral palsy (CP). CP is the most common physical disability in paediatrics, causing limited mobility, often due to spasticity. In the present PhD-thesis, effects of early intervention in infants at very high risk of CP are studied. Typical infant physiotherapy (TIP) has been compared with a new developed intervention method: COPing with and CAring for infants with special needs - a family centred programme. Interventions have been studied in two different projects: the VIP-project (2003-2005) and the LEARN2MOVE 0-2-project (2008-2015). After applying one of the two mentioned intervention methods, child and family outcome in the two groups was similar. Detailed analysis of the contents of the interventions, indicated several positive associations between specific COPCA-elements and outcome: with child outcome in the VIP-project and with family outcome in the LEARN2MOVE 0-2-project. Analyses of the contents of intervention showed increasing family involvement over the years in the TIP-intervention. To be able to study outcome of intervention studies adequately, appropriate measurements are needed. Therefore, some suggestions have been provided for specific motor measurements for infants at high risk of CP. With the results of this thesis, we hope to improve care for infants at very high risk of CP and their families