Thumb sucking

What the habit is

Thumb-sucking and pacifier use are put together under one name, nonnutritive sucking behaviors, because the same advice covers both.

They are considered a normal part of development and can have beneficial health effects: they promote the sensation of security and allow infants to self-soothe. The American Academy of Pediatrics recommends offering pacifiers to infants at the onset of sleep to reduce the risk of sudden infant death syndrome.

Whether to begin a pacifier at all is left to the preference of parents and caregivers, which multiple specialty guidelines support, because pacifier use has not been associated with decreased rates of breastfeeding in motivated mothers.

Natural history, and what reassurance rests on

Thumb-sucking is named among the common early childhood challenges that often resolve on their own, and the article states that most children spontaneously stop nonnutritive sucking behaviors between 2 and 4 months of age.

That is why the first move is education, guidance and reassurance rather than treatment.

The three ages, and what each one is for

This is the part that is asked about, and the three ages are not one age. Each is tied to a different harm:

• 6 to 12 months of age: pacifier use should be eliminated or decreased, to reduce the risk of recurrent otitis media. This is the recommendation of the American Academy of Family Physicians and the American Academy of Pediatrics.
• 3 years of age: nonnutritive sucking behaviors, pacifier use and thumb-sucking together, should be stopped, to reduce dental malocclusion. Beyond 3 years the article gives dental and social consequences.
• Age 5: the pediatric review pages put the question as up to what age is thumb sucking normal, and answer that thumb sucking is normal in infants and young children and should cause no permanent problems if it stops by age 5.

So the two files do not give the same age, and both are worth holding. The review pages answer the question as asked, up to age 5, and they give that age as a limit on permanent harm, not as an age at which anything is done. The article's own age for action is 3 years, and it is the age tied to malocclusion and to the dentist.