It is healthy and good for children to develop some special way of soothing themselves. It is important for children to learn to calm themselves down in your absence. And sometimes they may need a pacifier, blanket or favourite toy to help. Most children have some method for soothing themselves, and they grow out of it naturally.
You might find that your baby soothes herself by sucking, even when she is not feeding. Babies may suck on fingers, thumbs, their whole hand or a pacifier you give them. Other common ways that children soothe themselves are by twirling their hair, stroking their blanket, rocking themselves or hugging a favourite toy. This gives them a warm and constant companion when their parents are not around.
You'll probably notice that your child uses a security blanket or pacifier more when he is tired, worried or not feeling well. Doing so helps him to feel safe and comforted. Even if your child may have given up being dependent on a pacifier or security blanket, he may start needing it again if there are new stresses in his life. You, on the other hand, may find it frustrating to always have to worry where that special object is, or you might also be embarrassed that your child is sucking a pacifier or dragging a blanket around, because you think he is too old for it.
Try not to worry about this. Your child's attachment to this object is completely natural. So do not try to prevent it or take the object away. Also, avoid nagging or teasing your child about it by calling her a "baby" for using it. That will make things worse.
Remember, every child is unique. Some children will never use a security blanket or suck their thumbs, while many others do so for a large part of their early life. It's important to give the children who do soothe themselves in these ways the time they need to stop in their own way.
Usually, a child will stop fairly soon after she starts daycare or preschool. She'll want to seem like a "big kid" just like the other children. If other children tease your child, remind them not to tease, and that your child will stop when he is ready.
If your child sucks his thumb too much and too long after the age of five, he can damage the formation of his teeth. Consult your child's physician under these circumstances.