In Germany there are a few key milestone years that are heavily documented (forget which years) and every kid has to do that with their pediatrician. In the US it's typical to have an annual exam with their pediatrician - this is free and standard for everybody with health insurance (which includes medicaid and state programs). Unlike Germany though I think a parent could be disengaged and that would mean multiple years without a checkup. In Germany I think they'd know and check in on the family if those milestone checkups weren't done.