Thanks for posting your query here.
You have not mentioned about the current age of the your son.
As I understand, his Hb level at 3 months was 9.7 and currently it is 11.2.
Please be reassured, this Hb is just slightly lower than normal range. It should improve with adequate intake of iron and folic acid
(prescribed as Syrup by your doctor).
All the babies usually have a slight decrease in Hb levels around 3-6 months of age and then it picks up again (due to the way blood is being produced in babies body).
I hope I have been able to resolve your query.
Dr Tejas Shah