meri beti ki age 3.5 mnth h or bachho k according uski height nhi bd rhi h or 2-3 mnth k ander usse jukam ho jata h srdi m bhi or grmi m bhi plzz suggest what can I do

A. Sometimes due to allergies also despite of taking proper food and all the child does not gain weight so you need to figure out first what kind of an allergy is your child suffering from so that you can treat your child according to that