Hi....Mr.Maze..,
welcome to HCM..
Thanks for your query...,
Growth of the individual is very complicated issue..,
I will try to explain....
GROWTH HORMONE....
It is secrete from Ant.
pituitary gland in the Brain...
Fastest growth  seen in embryonic life (2 feet)..,
After only 3 growth spurts are seen at...infancy, childhood and 
puberty...,
It depends mainly on Nutrition......After 1 year...,
Endocrine factors come in the action...,
During the first 2 years of growth called...Catch up Growth...,
Childhood growth depends on GH and Thyroxin...,hence growth is faster..,
The growth spurt during puberty is due to both GH..,and Sex 
steroids...,
After Growth is very less..So evaluate where  growth is defective..?
consult good pediatric 
endocrinologist and follow accordingly....,ok.good luck