How do you think we can Prevent Child Abuse Effectively and Logically. Specially for children under 4yrs?

When children start school they have a greater chance of being helped because other people aside the abuser are around them but children under 4yrs or so don't go to school and some don't even go to daycare either. How could we reach those children that are not around other people to display the signs of abuse? 80% of fatalities in child abuse are children under 4yrs.