Sucking on thumbs, fingers, pacifiers or other objects is a natural reflex for children. It may make babies feel secure and happy and help them learn about their world.
Why it happens
Kids suck their thumbs because it’s comforting and calming. Your preschooler probably practiced this habit while she was still in the womb and perfected it as an infant.
Now she turns to her thumb when she’s tired, scared, bored, sick, or trying to adjust to challenges such as starting daycare or preschool. She may also use her thumb to help her fall asleep at bedtime and to lull herself back to sleep when she wakes up in the middle of the night.
What to do about thumb-sucking
Don’t worry too much. The American Dental Association says most children can safely suck their thumb – without damaging the alignment of their teeth or jaws – until their permanent teeth begin to appear. (Permanent teeth don’t usually start to erupt until around age 6.)
Keep in mind, too, that not all thumb-sucking is equally damaging; experts say it’s the intensity of the sucking and the tongue’s thrust that deforms teeth and makes braces necessary later. Kids who rest their thumbs passively in their mouths are less likely to have dental problems than children who suck aggressively.
Observe your child’s technique. If she sucks vigorously, you may want to begin curbing her habit earlier, say around age 4. If you notice any changes in her mouth or teeth, or if you’re unsure whether your child’s thumb-sucking is causing problems, consult your dentist.
If your child’s thumb becomes red and chapped from sucking, try applying a moisturizer while she’s sleeping. (If you apply it when she’s awake, it may just end up in her mouth.)
Most children stop thumb-sucking on their own between the ages of 2 and 4. Some continue the habit longer, but peer pressure in school is often a very effective deterrent.
Let it go. Punishing your preschooler or nagging her to get her thumb out of her mouth won’t help because she probably doesn’t even realize she’s doing it. Methods such as putting an elastic bandage on her thumb will seem like unjust punishment, especially because she indulges in the habit for comfort and security. Plus, pressuring her to stop may intensify her desire to do it even more.
Try to wait it out. Children usually give up thumb-sucking when they find other ways to calm and comfort themselves. If your child tends to suck her thumb when she’s hungry, for instance, she’ll soon learn to simply open the fridge and look for something to eat or ask you for a snack instead.
Preempt thumb-sucking with other activities. If you can identify the times and places when your preschooler is most likely to suck her thumb – while watching television, for instance – consider distracting her with a substitute activity, such as a rubber ball to squeeze or finger puppets to play with.
If she tends to suck her thumb when she’s tired, you could try letting her nap longer or moving up her bedtime. Or if she turns to her thumb when she’s frustrated, help her put her feelings into words.
The key is to notice when and where sucking occurs and try to divert her attention by offering an alternative. Together, you and your child can find solutions that will – eventually – help her kick the thumb habit.