Why Does Your Child Suck Her Thumb and Should You Stop It?

If you’re worried about your baby’s thumb-sucking, take heart. Until your little one turns about 5 years old, there isn’t any risk associated with thumb-sucking, so it’s only really closer to then that you might consider helping help her stop the habit, if she hasn’t already. Read on to learn more about why babies and children suck their thumbs, when the behavior typically starts, and how to stop thumb-sucking when the time comes.

Why Do Babies and Children Suck Their Thumbs?

Babies are born with natural rooting and sucking reflexes, which is why some infants will put their thumb or fingers in their mouth and suck.

Thumb-sucking also has a soothing and calming effect for babies and young children. It can help your little one feel secure and comforted, which is why she may pick up the thumb-sucking habit when she needs a little soothing or before bed, for example. So, don’t worry too much about it: It’s perfectly normal for your little one to suck her thumb.

When Do Babies Start Sucking Their Thumb and When Do They Stop?

Thumb-sucking often starts at a very young age. Some babies begin sucking their thumbs and fingers in the womb! And, some newborn babies start sucking their thumbs as soon as they have been born. There are even babies who won’t go on to suck their thumbs.

Once your little one starts, it can easily become a habit, especially as your little one likely finds it so comforting. It's helpful to remember that thumb and finger sucking is a common habit—and that all kids have habits—so you have no need to worry if your baby is sucking her thumb regularly.

Most children grow out of this behavior. In fact, more than half stop when they are 6 or 7 months old. Others stop naturally a little later between the ages of 2 and 4 years old.

In some cases, perhaps if your little one is feeling extra vulnerable or stressed, she may even suck her thumb on occasion until she’s about 8 years old.

When Should You Try to Help Your Child Stop Thumb-Sucking?

Although thumb-sucking is normal for young children, if it goes on beyond the age of about 5, it can become a concern. This is because once the permanent teeth start coming in, thumb-sucking can affect the shape of the mouth and affect how the teeth line up.

Once your child is about 4 or 5 years old, it may be time to wean him off this habit.

If your little one is still a baby or toddler and you’re worried about how his thumb-sucking may affect the development of his mouth, gums, or baby teeth speak to your little one’s healthcare provider or dentist for personalized guidance.

How to Stop Your Baby’s or Child’s Thumb-Sucking

For a baby, you don’t need to! It’s perfectly OK for your baby to be sucking his thumb. Once your child is nearing 5 years old or is any older and still thumb-sucking, you can work with him to help change the behavior.

Keep in mind, it won’t happen overnight and you’ll need to be patient with your little one.

When starting the process, make sure that your child is in a happy place. Stress and emotional problems may make him more resistant to changing the behavior, as thumb-sucking gives him some comfort.

If you know there is something that is causing stress for your child out, try to take care of that before concentrating on trying to break the thumb-sucking habit. For example, if you’re moving to another house or if he’s getting a sibling soon, it may be better to wait for things to settle down.

Here are a few things you can do to help your child stop thumb-sucking:

  • Offer regular, gentle reminders. Your little one may not realize he is sucking his thumb, so remind him calmly that he is doing it and that it’s not good for him. Be kind and reassuring and avoid scolding or criticizing him.

  • Understand the triggers. Is there something that stresses your child and that causes him to suck his thumb? Does he have separation anxiety when you go to work or when you drop him off at kindergarten? Does he do it at a certain time of day or place? If you’re not sure what is causing the stress, talk to him about it and try to avoid the triggers if you can. If your child seeks comfort before going to bed by sucking his thumb, you can take a few measures to help him get a better night’s sleep, such as giving him a bath before bed or reading him a bedtime story.

  • Use positive reinforcement. Set small goals to encourage him, like no thumb-sucking an hour before bed (and then none after dinner, then not doing it all day, for example). Reward him with encouragement and praise, or a specific reward, each time he goes the full time without thumb-sucking.

  • Consider aversive measures as a last resort. If, after a while, you notice your child is still thumb-sucking, even after trying the above ideas, consult your child's healthcare provider for advice. Your provider may recommend aversive measures, like coating the thumb or finger with a bitter substance, or by using a bandage or thumb guard to discourage your child from sucking.

  • Talk to your child’s dentist. If your little one can’t break the habit, your child’s dentist can provide a personalized recommendation on what to do to protect your child’s teeth and mouth.


Thumb-sucking offers comfort and can be soothing for your baby, but there are no specific health benefits. In children under 5 years old, it’s generally harmless, but it can cause problems for the mouth and permanent teeth in older children.

The Bottom Line

Thumb-sucking in babies is not something to worry about. It's a common behavior that provides comfort for many babies and young children. Chances are your little one will stop doing it naturally by about the age of 4, if not earlier.

Even if you notice that your little one is occasionally sucking his thumb after he turns 5, it shouldn’t cause problems for the development of his mouth and teeth.

However, if it’s a regular thing and the habit doesn’t look to be going away when your child reaches about age 5, there are some simple things you can do to help him break the habit. Gentle reminders to stop, positive reinforcement when your child goes long stretches without thumb-sucking, and eliminating or reducing stressors might work well.

Patience and consistency on your part, and help from your child’s healthcare provider or dentist if it’s needed, will help your little one conquer the thumb-sucking habit once and for all.

While you’re here, you may also be interested in reading our guide on dental care for children, including how to brush your little one’s teeth, what to do about common teeth injuries, and more.

How we wrote this article The information in this article is based on the expert advice found in trusted medical and government sources, such as the American Academy of Pediatrics and the American College of Obstetricians and Gynecologists. You can find a full list of sources used for this article below. The content on this page should not replace professional medical advice. Always consult medical professionals for full diagnosis and treatment.

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