My baby is 5 month old but her head circumference is same since 3months and her weight gain has not even doubled her birth weight.

A. hello. if the baby has not shown any weight game then there is something to worry about. but if there is some weight gain even if it is not the double of the birth weight and the baby is taking their feed properly is happy e healthy and showing normal behaviour then there is nothing to worry about full stop sometimes some children take a while to reach a normal milestone