Thumb-sucking is normal in babies and young children. Thumb sucking is a common way babies seem to comfort themselves. A child usually sucks his thumb when he is tired, bored, sick, or upset or when he is not using his hands to play. Thumb sucking usually begins by 3 months of age but should decrease by age’s three to four and stop by age five. Most children give up thumb-sucking during their toddler years but 15 per cent are still doing it at the age of four.

Children who suck their thumbs frequently or with great intensity after the age of 4 or 5 or those who continue to suck their thumbs after age 5 are at risk for dental or speech problems. Thumb-sucking can cause a child’s teeth to become improperly aligned (malocclusion) or push the teeth outward, as well as damage the growth and formation of the upper palate (roof of the mouth). A child may also develop speech problems, including mispronouncing Ts and Ds.

In some cases, thumb-sucking after age 5 is in response to an emotional problem or other disorder, such as anxiety. A child with this type of problem needs to be evaluated by a doctor. Most other children stop sucking their thumbs after simple treatment measures are introduced.