I hear from moms of babies around 4 months of age that they think their baby might be teething. A lot of babies at this age start displaying behaviors that look like symptoms of teething in older children. They start drooling a lot, and look like they’re biting and chewing on everything. However, getting the first two teeth at this age would not be usual. The average for the first two lower teeth to make an appearance is at about 6-10 months, right in time to try out new foods. I’m not saying it’s not possible for babies to get their first teeth at 4 months, but it’s pretty far outside the average compared to the number of babies who I hear about having “teething” behaviors at this age. So what’s going on that makes babies who are probably not teething look like they are?
The dance of mother/baby development in the first few months after birth amazes me. It’s incredible how the mother’s body works to accommodate a growing baby by making milk with different nutritional qualities as her baby grows. The reflexes and small adaptations babies develop that precede and prepare them for major developmental milestones also amaze me. The things that happen in a baby’s body to prepare for eating solid food are exquisitely choreographed to allow babies to start to feed themselves at just the right time, all coming together between 4 and 6 months of age for healthy babies, with readiness for solids actually beginning at 6 months of age.
When this appearance of early teething behavior occurs, to things are usually seen: drooling and chewing. Teething older children do these two things for a week or two before getting a new tooth, but in many babies right at 4 months or so of age have these two behaviors that precede tooth eruption by several weeks or even months. Also at 4 months, a lot of babies have about 6 weeks of sleep disturbance that is very common and sometimes lumped together with these behaviors and called “teething.” Since there is no tooth eruption imminent at most babies at this age, something else is probably going on that prompt these things that are completely unrelated to teething. I’m not doubting that parents see this drooling, chewing, and sleep disturbance at 4 months. I’m also in no way denying that when older babies are days away from cutting new teeth that they do these things. However, I am saying that there are other reasons why a 4 month old may experience what looks similar to teething when their first teeth are still at least 2 months away.
Let’s look at drooling first. It’s pretty normal and common for babies between 3 and 6 months to drool. A lot. Some babies even need to wear a bib to keep their clothes from getting soaked. It’s usually not a problem, except that some babies end up with a rash on their chins from the constant wetness. If this happens, you can occasionally dry the baby’s chin and apply a natural and edible barrier cream, like Earth Mama Angel Baby Nipple Butter or plain old coconut oil. (BTW, I don’t really recommend using your diaper cream for this, even if it’s a natural and edible one for the simple reason that you use it at the changing table. Probably someone has touched the baby’s butt and then put their fingers in the diaper cream jar, so then using it on the baby’s chin has a major yuck factor, if you think about it.) Drooling is certainly a teething symptom in older children, but in a 3 or 4 month old, there is a more likely explanation. Starting at about 3 or 4 months of age, babies start producing more saliva in preparation for eating solid foods. Preparing for a lifetime of eating food is a major developmental step that doesn’t happen overnight. Saliva is more than just liquid that keeps your mouth wet; it contains digestive enzymes. Mixing and mashing food in your mouth along with saliva is the first step in digesting food. Babies who are fed only liquid diets, which they should be at this age, don’t need a lot of extra saliva. But as the time for starting solids approaches, their mouths do start producing the extra saliva needed for digesting food right at about 3 to 4 months of age. While the extra saliva is a sign of impending readiness for solids, it should be noted that its presence in itself is not indicative of readiness to start solid food. It’s just one step in the process. Babies also don’t don’t swallow their saliva, so they drool the extra out of their mouths. The drooling at 3 or 4 months is almost universal, and unless a tooth is actually seen erupting is probably not a sign of teething, but just a developmental milestone in digestion.
The other symptom of concern here is biting or chewing. It’s well known that babies who are teething like to bite and chew. But babies at 3 or 4 months will also make a rhythmic chewing motion if something like a teething ring (or food, or their own finger) is put in their mouths. This is, again, something that mimics teething behavior in older children that can be explained by a normal earlier stage of development.
Before 6 months of age, a great many infant behaviors are driven by reflexes. There are a whole lot of things that your baby will do automatically and in the same way each time in response to certain movements or touches. A simple one to see is the asymmetrical tonic neck reflex. You’ve probably seen it and not thought anything about it. If a baby’s head is turned to one side while lying on her back, she’ll extend the arm on the side she’s looking straight out. The other arm turns upward. It’s sometimes called the Fencer’s Reflex because the baby looks like the baby’s ready for sword fighting. There are a whole lot more of these reflexive behaviors going on, too. One of them, the phasic bite reflex, is relevant to our discussion. This reflex is present at birth in full term infants. If you rub or put pressure on a baby’s lower gums, the baby will have a reflexive behavior of opening and closing the jaw, like chewing. However, it’s an automatic behavior created in the nervous system, and not really voluntary chewing for pleasure or pain relief as seen in older children who are teething. Like the drooling, this reflex is part of biological preparation for eating. It ensures that when babies do start to eat solid food, they will chew it. The phasic bite reflex goes away between 9 and 12 months, so it’s not responsible for what we see in teething babies past that age. The 4 month time frame also corresponds to when many babies start to put things into their own mouths, and at that time we see them stimulating their own phasic bite reflexes really for the first time. So what do we see? A drooling baby putting everything in her mouth and chewing on it. It looks a lot like an older baby teething, but is probably happening for completely different reasons that are also normal and biologically sound.
Lastly, the sleep disturbance. Teething in children whose teeth are actively erupting is painful, and often causes them to wake in the night. However, it’s observed that many babies at the age of 4 months go through a period of increased night waking. It’s so well known that it has a name: the 4 Month Sleep Regression. Whether its a sleep “regression” is a matter of perspective, but it’s extremely common. When babies go through this stage, they wake more frequently in the night than they previously did and it lasts about 6 weeks. No one really knows why this happens. There are a few theories for the cause. The most common that I’ve heard is that it corresponds with a baby’s increased awareness of the world outside of themselves. Basically, that they start to notice the world and get too distracted to go back to sleep. It can be incredibly distressing for parents. Many have reported to me that they never get more than an hour of uninterrupted sleep during this period. It’s made worse by the fact that this comes at the same time that many mothers are newly returning to work. Parents can get desperate. Some parents get so distressed by the 4 month sleep regression that they prematurely start solids in the form of cereal in the bottle to try to increase the length of baby’s sleep. (Please be aware, this practice has been shown to NOT help with infant sleep and is not recommended.) Others start using sleep training methods like extinguishing to try to get their babies to sleep like they used to right at this time. No one really knows how prevalent the 4 month sleep regression is nor what causes it, but it’s common enough that it probably doesn’t account for the small number of babies that get their first teeth at this age. Something else is going on. I’m not sure what, but I’m hoping to study it some day.
Babies’ first teeth erupt, on average, at 6-10 months of age. This is the biologically average age of first teeth. Getting teeth much before that is not unheard of, but it is unusual. However, many moms report “teething” behavior two or more months before the eruption of the first tooth. Seeing as how this behavior is much more common than it is for babies to get teeth before 6 months of age, and also that teething behavior does not generally last for weeks or months before later teeth come in, there is probably something else going on. As it turns out, there are other explanations for the cluster of behavior that includes chewing, drooling, and sleeplessness in babies around 4 months of age. At this age, babies’ bodies prepare for introducing solid foods by increased production of saliva, the source of the drool. They also at this age have an automatic reflex that can cause them to appear to be ravenously chewing on anything in their mouths. Considering that many people feel that babies should wean when they get teeth, identifying what is and isn’t teething could be important to a baby’s well being. Understanding that a 4 month old baby that is chewing and drooling may not actually be Keeping these normal developmental stages in mind when drooling, chewing, and sleeplessness appear significantly before the first tooth is expected may help parents understand their babies’ behavior and could reduce unnecessary intervention, anxiety, and weaning.