If you really think about it, your baby probably spends more time with his hand in his mouth during his first year of life than he does with it anywhere else. Some babies are so excited about their hands that it's almost hard to separate hand from mouth when you're trying to get them changed or bathed. It can be baffling as a parent, but here's why your baby keeps putting their hands in their mouth.
Babies put their hands in their mouths for a few reasons, including exploring the world around them as well as teething. Babies Online explained, "While discovering his hand is a normal occurrence for all babies, it can also be a sign of teething and a way that a baby begins to sooth himself when tired or fussy." Therefore, your baby putting her hands in her mouth might mean something different depending on her age.
Getting his hands in his mouth is actually an early milestone. Your baby will start to be able to bring her hands to her mouth between one and three months old, but they don't necessarily have the "strength of skills to keep them there," explained Parenting Counts. The site reported that "By 4 months, however, babies can put their hands in their mouths and keep them there (if they choose)."
Your baby might be putting her hand in her mouth just because it's the only thing she can reliably get in there to gum on, as she might be starting to teethe. Babies Online explained that there's another key sign you'll notice if your baby is starting the seemingly never ending teething process: "If there is a lot of excess drool, it probably means that your baby is starting to teeth and that they are putting pressure on their gums with their fists." Chewing on their fingers shouldn't create much of a problem for them, but you can offer a teething toy instead if you like. Paradoxically, babies often like teething toys that are harder rather than too soft; the hardness is what actually relieves pressure on the gums.
If your baby doesn't seem to be producing a puddle of drool every hour but still has his hands in his mouth, keep an eye on the time you notice it. It might be a trend that could indicate your baby is trying to soothe himself with his hands or fingers. Not all babies suck their thumb, they might suck one or two fingers in a specific way over and over again, which can help them nod off to sleep.
Baby Gaga explained that your child sucking their thumb or fingers "is natural for babies." In fact, the site reported, "Technicians can sometimes see babies sucking their thumbs when they are inside the mother’s womb." So sucking their thumb is a sign of self-soothing even when they are a fetus. This is not only natural, but hopeful. According to the site, "Babies need to learn to self soothe because mom or dad can be at their side 24/7."
Sucking a thumb can be a troublesome habit in part because it can lead to teeth coming in crooked and the mouth developing unnaturally, necessitating braces later on. However, it isn't likely a problem for your baby until they get older. The American Dental Association reported, "Sucking on thumbs, fingers, pacifiers or other objects may make babies feel secure and happy and help them learn about their world." Most give up between 2 and 4 years old, or before permanent teeth come in, in which case it shouldn't cause a dental problem for your baby to have his hands in his mouth.
Finally, babies put their hands in their mouths because it's one of the exploratory senses that develops earliest. Jill Stamm, Ph.D., co-founder of the New Directions Institute for Infant Brain Development and an associate clinical professor of psychology in education at Arizona State University in Tempe, told Fit Pregnancy that "The mouth and hands have the most neural real estate in the entire body," which is why babies always seem to want to get anything and everything into their mouths. "Babies get the most sensory input from those areas," so getting something into their mouths tells them about it quickly. While it might be a little slimy, your baby putting his hand in his mouth is most likely totally normal.