Why do children suck their thumbs?

“Thumb sucking (or any finger) is a natural reflex that many babies and toddlers use to self-regulate and self-soothe. Thumb sucking can help little ones feel safe, calm, and comforted,” says Jennifer Gillette MA, Child Development and Behavior specialist at Summer Health. Beginning in utero, babies have an instinctive need to suck, and it's the same reflex they use to feed from a breast or bottle. This sucking motion helps them feel calm, secure, and safe.

Thumb sucking is a form of self-regulation. It helps children manage their emotions and feel comforted, especially when they’re hungry, tired, uncomfortable, or overwhelmed. As children grow into toddlers and beyond, they may continue to suck their thumbs to cope with frustration, stress, or when they struggle to verbally express their needs.

Common reasons children suck their thumbs

• For comfort and emotional self-soothing

• To fall asleep when they’re tired

• To calm down when stressed or overstimulated

• To feel secure (much like using a favorite blanket or stuffed animal)

“Seeking emotional comfort is a natural part of early childhood development and often shows up through attachment behaviors like thumb sucking, crying, and reaching to be held, explains Gillette. "All children's behaviors have meaning. Think of the behaviors as a form of communication. Thumb sucking can be a child’s way of saying, ‘Right now I need to feel safe and soothed.’”

When does thumb sucking become a concern?

To clarify, thumb sucking is not a bad habit for babies. It’s a normal and healthy part of early development. It helps infants self-soothe and regulate their emotions before they develop language or other coping strategies. However, if thumb sucking continues beyond the toddler years (typically past age 3 to 4), it can interfere with oral development. Some potential issues include:

• Misaligned teeth

• Bite issues (like overbite or crossbite)

• Changes to the shape of the roof of the mouth (palate changes)

• Delayed speech development

According to the American Academy of Pediatrics (AAP), if a child stops thumb sucking before the permanent front teeth come in, the bite will likely correct itself. If not, and the adult teeth stick out, orthodontic treatment may be needed to correct the bite.

Thumb sucking and social challenges

Additionally, thumb sucking can lead to social challenges as children get older. They may be teased by peers at school or receive comments from others in public, which can cause feelings of embarrassment, guilt, or shame. “When a child is old enough to be aware of others’ reactions, thumb sucking can shift from a soothing behavior to one that creates social anxiety. Even subtle cues can make a child feel self-conscious,” says Gillette. 

When should children stop thumb sucking?

It’s best to encourage children to stop thumb sucking by age 4, or earlier if it begins to affect their speech or dental development. Many children naturally outgrow the habit between ages 2 and 4. If it continues beyond age 5, gentle guidance and support may be needed.

Strategies to break the thumb sucking habit

The first step in helping a school-age child break the habit is to explain (using age-appropriate language) why it’s important to stop (to protect their teeth). For example you could say,”Your teeth are growing strong and straight, and sucking your thumb can push them out of place. Let’s help your teeth stay happy and healthy!"

Give them time to adjust and offer gentle reminders along the way. If that alone isn’t effective, try these supportive strategies:

• Praise thumb-free moments: Notice and celebrate small wins, like “I saw you didn’t suck your thumb while watching TV—that’s awesome!”). 

• Avoid punishment or shaming: Shaming can damage self-esteem and increase anxiety, which may worsen the habit. Focus on encouragement and emotional connection instead. “When children feel criticized or embarrassed, it often makes them more anxious—and that anxiety can lead to even more thumb sucking as a way to cope. What helps most is support, patience, and gentle redirection,” Gillette explains. 

• Involve your child in the process: Empower your child by creating a “thumb plan” together. Use a visual chart to track progress and offer a sense of autonomy and achievement.

• Identify triggers: Help your child become aware of when they tend to suck their thumb. Common triggers of thumb sucking include moments of fatigue, stress, boredom, or hunger.

• Offer alternative comfort items: Fidget toys, a soft blanket, or a favorite stuffed animal can replace the thumb and serve as a comfort item.

• Try gentle reminders: Use a nonjudgmental cue word or a visual signal to help your child become more aware and pause thumb sucking. 

• Use a nighttime support: If thumb sucking mainly happens during sleep, consider a soft glove or thumb guard as a gentle deterrent.

Should parents stop thumb sucking in babies?

No—thumb sucking in babies is completely normal and developmentally appropriate. It’s a natural self-soothing tool that helps with sleep and self-regulation skills. Breaking this habit too early can cause unnecessary stress and take away important coping mechanisms before the baby has developed other ways to self-regulate. However, if the sucking is overly forceful or interferes with feeding, it’s best to consult a pediatrician or pediatric dentist for additional guidance and support. 

FAQs

Are pacifiers better than thumb sucking?

Yes, pacifiers are generally better than thumb sucking. "Pacifier use is easier to manage and eventually stop compared to thumb sucking, because it's not part of the child's body and can be gradually taken away," Gillette explains. 

When do babies learn to self-soothe?

At first, babies rely entirely on caregivers to help them regulate ( through soothing, feeding, rocking, etc.). Between 3 and 6 months babies start to self-soothe, like turning their head away from overstimulation or sucking their thumb to calm down. “Babies start learning to self-regulate from day one, but they need lots of love, comfort, and consistency from their caregivers to build these skills over time,” says Gillette.

Can children stop thumb sucking on their own?

Yes, children can stop thumb sucking on their own, especially as they become more socially aware—usually between age 2 and 4. However, some children continue the habit, especially when they’re tired, anxious, or seeking comfort.

Does thumb sucking cause oral infection?

Thumb sucking is not a significant risk factor for oral infection but it can definitely make it more likely for a child to get sick. Children frequently touch toys and other objects that may carry viruses, and pass it along to other kids. They also put them in their mouths. If your child is a thumb sucker,  be sure to be on top of frequent hand washing. 

Are baby pacifiers bad or good? 

When babies suck on a pacifier, a thumb, or any other object that doesn’t result in drinking milk, it’s called non-nutritive sucking. Non-nutritive sucking can be helpful for babies’ growth and development, especially for preterm babies. 

Research done in preterm babies, for example, shows non-nutritive sucking helps preterm babies better transition to eating by mouth and can even shorten the length of hospital stays. Non-nutritive sucking can also help babies comfort themselves, reduce stress, and strengthen the suckling muscles for feeding. Many pediatricians will start preterm babies on a pacifier shortly after birth.

Beyond the growth and development benefits, there are several other benefits to using a pacifier, such as:

• Lowering the risk of sudden infant death syndrome (SIDS)

• Soothing fussy or colicky babies

• Helping babies fall asleep

If you have questions about thumb sucking or how to stop your child from sucking any finger(s), reach out to your local or Summer Health pediatrician for support. Summer Health is a pediatric telehealth platform offering 24/7 care, providing answers for everything from urgent concerns to everyday questions about your child’s health.