We are all aware that babies are born with natural rooting and sucking reflexes. The foregoing is the reason why some infants will put their thumb or fingers in their mouth and suck.
Thumb-sucking also has a soothing and calming effect for babies and young children.
It can sometimes help your little one feel secure and comforted, which is why she may pick up the thumb-sucking habit when she needs a little soothing or before bed, for example.
So please do not worry too much about it.
It is perfectly normal for your little one to suck her thumb.
When Babies Start Sucking Their Thumb and When They Stop?
Thumb-sucking often begins at a very young age.
Some children start sucking their thumbs and fingers in the womb.
Other newborn babies begin sucking their thumbs as soon as they have been born.
Do you know that there are even babies who won’t go on to suck their thumbs? Yes there are.
Once your little one starts, it can easily become a habit, especially as your little one likely finds it so comforting.
It is very helpful to remember that thumb and finger sucking is a common habit and that all kids have habits so you have no need to worry if your baby is sucking her thumb regularly.
Majority of children grow out of this behavior.
As a matter of fact, more than half stop when they are 6 or 7 months old. Others too stop naturally a little later between the ages of 2 and 4 years old.
Source; www.leakynews.net