Developmental achievements are called ‘milestones’. Growth and development milestones are a useful guide but nothing more – they don’t mean much beyond offering some kind of age range or guide to ‘what’s normal’.
Developmental progress can be delayed for all kinds of reasons. Premature birth and illness are two things that might cause temporary delays. Some disabilities can cause permanent delay. A child’s development can also suffer because of her environment.
All babies develop in the same order but at completely different rates. One seven-month-old might be crawling around and chattering madly; another might be playing silently on his playmat.
Developmental milestones can be grouped under headings such as: