Most of the time, a baby shaking his head side to side is completely normal and nothing to worry about. Infants discover head movement early, often as a way to explore how their body moves, to self-soothe before sleep, or eventually to start communicating. In a small number of cases, though, repetitive head shaking can signal ear discomfort, reflux, or a neurological condition worth investigating. Understanding the full range of reasons helps you sort the harmless from the ones that deserve a call to the pediatrician.
Exploring How the Body Works
Babies are born into a world they understand almost nothing about, including the layout of their own bodies. One of the earliest systems they begin exercising is the vestibular system, the sensory apparatus in the inner ear that detects motion and orientation. Head movements in space send vestibular signals that help the developing brain build representations of where body parts are relative to one another and how the body is oriented in the environment.1Frontiers in Integrative Neuroscience. Vestibular activity and cognitive development in children: perspectives Shaking the head side to side is one of the simplest ways a baby can generate this kind of input. You might notice it during tummy time, when your baby is experimenting with neck control, or while lying on his back just moving for the sake of moving.
This kind of exploratory head shaking tends to come and go. It usually starts around three to four months, when babies gain enough neck strength to control the motion, and can persist through the first year. It is not rhythmic in the way a seizure would be, does not seem to distress the baby, and typically stops when something grabs his attention. If your baby looks happy or curious while doing it, you are almost certainly watching a healthy brain figuring out how movement works.
Self-Soothing at Sleep Time
If you notice the head shaking mostly at bedtime, naptime, or during the transition into sleep, your baby is likely using the repetitive motion to calm himself. Some babies rock their whole body, some bang their head gently against the mattress, and some shake their head from side to side. The rhythmic quality of the movement is soothing in the same way that rocking in a chair or swaying a baby back and forth is soothing. It takes advantage of that same vestibular system: steady, predictable motion quiets arousal.
Sleep-related head shaking can look alarming the first time you notice it, especially if it seems vigorous. But babies who self-soothe this way are not in pain and are not having a neurological event. The behavior tends to peak between six and nine months and gradually fades as children develop other ways to wind down. If the shaking is confined to the minutes around falling asleep and your baby sleeps normally afterward, it almost never requires any intervention.
Learning to Say No
Somewhere around the end of the first year, head shaking starts to mean something new: communication. Research tracking infant gesture development found that while young infants can physically shake their heads side to side early on, they do not use the movement to communicate refusal at first. In a diary study, shaking the head for “no” emerged in all of the infants between 13 and 15 months, and a full understanding of the gesture as a response to someone else’s statement took even longer to develop.2Gesture. Developing gestures for no and yes: Head shaking and nodding in infancy
Before babies reach that communicative stage, though, they often practice the motion. You might see your nine-month-old shaking his head during a meal or during play without any clear intent to refuse something. He may be imitating you, testing the reaction he gets, or simply enjoying the sensation. This transitional period, where the physical skill exists but the meaning has not yet been attached, accounts for a lot of the head shaking that puzzles parents of older infants. Once your child starts pairing the shake with a clear “no” or with pushing something away, the mystery solves itself.
Ear Discomfort and Infections
Babies cannot point to their ear and tell you it hurts, so they communicate discomfort through behavior. A prospective study that followed over 100 infants presenting with ear-related behaviors, including tugging and pulling on their ears, rubbing their ears on a shoulder or pillow, and shaking their heads, found that these movements were a common reason parents brought their babies in for evaluation.3PubMed. Why do infants pull their ears? Middle ear infections, fluid buildup, and even teething pain that radiates to the jaw and ear area can all provoke head shaking as the baby tries to relieve pressure or an unfamiliar sensation.
The clues that ear trouble might be driving the behavior are usually straightforward. A baby shaking his head because of ear discomfort is often fussy, may have a fever, and tends to shake more on one side or pair it with ear-pulling. He may cry more than usual, particularly when lying flat, because the position increases pressure in the middle ear. If the head shaking appeared suddenly, coincides with a cold or upper respiratory symptoms, or comes with visible irritability, a check of the ears is a reasonable next step. Most ear infections in babies are highly treatable and resolve quickly with appropriate care.
Reflux and Sandifer Syndrome
Gastroesophageal reflux, where stomach acid flows back into the esophagus, is common in babies. Most of the time it shows up as spit-up and occasional fussiness. In a small subset of infants, though, reflux triggers an unusual movement pattern called Sandifer syndrome, a combination of abnormal posturing of the head and neck, arching of the back, and twisting or turning motions that can include side-to-side head shaking.4PubMed Central. A systematic review of Sandifer syndrome in children with severe gastroesophageal reflux
The movements in Sandifer syndrome look strange enough that they are frequently mistaken for seizures. One case report described a five-month-old admitted to a pediatric unit because the episodes looked like infantile spasms, a serious type of epilepsy. The neurological workup came back normal, and the movements disappeared once the underlying reflux was treated.5PubMed. Sandifer’s syndrome in a 5-month-old child with suspicion of infantile spasms The syndrome is considered uncommon and often takes a long time to diagnose, partly because the link between a head movement and a stomach problem is not intuitive.4PubMed Central. A systematic review of Sandifer syndrome in children with severe gastroesophageal reflux
If your baby’s head movements tend to happen during or after feedings, come with back arching, and seem to involve an element of discomfort or straining, mentioning reflux to your pediatrician is worthwhile. The good news is that when Sandifer syndrome is the cause, treating the reflux resolves the abnormal movements. The bad news is mainly the diagnostic detour: families sometimes go through extensive neurological testing before anyone connects the movements to the gut.
Shuddering Attacks
Shuddering attacks are brief episodes where a baby’s head and upper body shiver or tremble rapidly, almost like a quick, exaggerated shiver from cold. They can look genuinely alarming, but they are a benign phenomenon. The episodes are involuntary, happen during normal activities, and do not affect consciousness. A baby in the middle of a shuddering attack may pause for a second or two and then go right back to whatever he was doing. A normal neurological exam and a normal brain-wave recording confirm the diagnosis, and no treatment is needed.6PubMed Central. Shuddering attacks: A benign phenomenon in children
Parents sometimes confuse shuddering attacks with seizures because the rapid trembling can look like shaking. The key differences are duration and awareness. Shuddering attacks last only a few seconds, the baby stays alert and responsive during and after, and there is no drowsiness or confusion afterward. Seizures in infants tend to involve more rhythmic, sustained movements, changes in consciousness, and sometimes eye deviation. If you can capture the episode on video and show it to your pediatrician, that single step can often resolve the question quickly. Most children outgrow shuddering attacks without any lasting effects.
Spasmus Nutans
Spasmus nutans is a rare condition that shows up in infancy, usually between about four months and a year and a half of age. It involves a triad of symptoms: involuntary eye oscillations (rapid jiggling of the eyes), head nodding or shaking, and an abnormal head position such as a tilt or turn.7JAMA Ophthalmology. Spasmus Nutans: A Quantitative Prospective Study The head movements can be side-to-side or up-and-down, and the eye movements are often subtle enough that parents notice the head shaking long before anyone spots the nystagmus.
In one reported case, a 23-month-old boy presented with nystagmus, head shaking, and a head tilt suggestive of spasmus nutans, with examination revealing bilateral, low-amplitude, high-frequency eye oscillations that were more prominent in one eye.8Acta Medica Philippina. A Rare Case of Spasmus Nutans in an Infant Classic spasmus nutans is considered benign and typically resolves on its own within a few years. The reason it matters, though, is that the same combination of symptoms can occasionally be caused by a tumor or other abnormality along the visual pathway. When spasmus nutans is suspected, pediatricians usually order brain imaging to rule out those rarer and more serious causes before settling on the benign diagnosis.
If your baby is shaking his head and you also notice unusual eye movements, a persistent head tilt, or trouble tracking objects visually, bring it up with your doctor. These signs together form a pattern that is distinct from the normal developmental head shaking described earlier.
Head Movements and Autism Spectrum Disorder
One question parents often have, especially if they have been reading online, is whether repetitive head shaking could be an early sign of autism spectrum disorder. Repetitive movements, called stereotypies, are one feature of ASD, and research has examined whether certain early motor patterns can distinguish infants who later receive a diagnosis. One study looking at spontaneous head position and movement found that infants who later developed ASD showed lower ability to maintain a midline head position during early infancy compared to typically developing infants.9PubMed. Early motor signs of autism spectrum disorder in spontaneous position and movement of the head
That finding is about head control and positioning, not about the common side-to-side shaking that most parents are asking about. The research in this area is looking for subtle motor signatures that might eventually help with earlier detection, but no single behavior like head shaking is a reliable marker on its own. ASD is diagnosed based on a cluster of developmental differences that typically become more apparent after the first birthday, including delays in social engagement, limited eye contact, absence of pointing or joint attention, and reduced response to a child’s name being called. Isolated head shaking in an otherwise socially engaged, babbling, interactive baby is not a red flag for autism.
That said, if your baby’s head shaking is accompanied by other concerns, such as not making eye contact, not responding to sounds or his name, not babbling by around nine months, or seeming unusually withdrawn, raising those observations with your pediatrician is always the right call. Early intervention for developmental differences makes a meaningful difference in outcomes, and pediatricians are trained to screen for these patterns at well-child visits.
When to Call the Pediatrician
Most head shaking in babies does not need medical attention. But certain patterns warrant a visit. A practical way to think about it is to look at what happens around the head shaking, not just the shaking itself.
- Fever or cold symptoms: Head shaking paired with irritability, pulling at the ears, and signs of illness suggests a possible ear infection.
- Feeding-related timing: Episodes that cluster during or after meals, especially with back arching or visible discomfort, point toward reflux and possibly Sandifer syndrome.
- Eye movements: If you notice the eyes jiggling, a persistent head tilt, or trouble following objects, spasmus nutans or another visual-pathway issue should be evaluated.
- Loss of awareness: Any episode where your baby seems to “check out,” becomes unresponsive, or is drowsy and confused afterward needs prompt evaluation to rule out seizures.
- Developmental stalling: If head shaking appears alongside a plateau or regression in milestones like babbling, reaching, or social engagement, a developmental screening is appropriate.
Recording the episode on your phone is one of the most useful things you can do before the appointment. Doctors can glean more from ten seconds of video than from several minutes of a parent’s verbal description, because the rhythm, speed, and context of the movement all matter for distinguishing benign from concerning causes.
What About Head Banging?
Head banging, where a baby rhythmically bumps his head against the crib rails, the mattress, or even the floor, often gets lumped together with head shaking in parents’ minds. The two behaviors overlap in timing: both tend to peak in the second half of the first year and into toddlerhood, and both can serve a self-soothing function. Head banging during the pre-sleep period is remarkably common, estimated to occur in a sizable minority of toddlers, and is considered a normal sleep-related rhythmic movement.
The main practical concern with head banging is injury, not neurological disease. If your baby is banging his head hard enough to leave marks or bruises, padding the crib and ensuring the sleep environment is safe becomes the priority. Most children stop on their own by age three or four. Like head shaking, head banging in isolation is not a sign of a neurological problem, but head banging that persists well into childhood, intensifies rather than fading, or occurs alongside developmental concerns does justify a discussion with your pediatrician.
Teething as a Trigger
Teething deserves a mention because it accounts for a surprising number of parental “why is my baby doing this” searches. When teeth are working their way through the gums, particularly the molars, the discomfort can radiate along the jaw and up toward the ear. Babies often respond by shaking their heads, rubbing their faces on surfaces, and chewing on anything they can reach. The timing of teething, which varies but commonly begins around six months, overlaps neatly with the developmental window where exploratory head shaking is also happening. This makes it hard to tell the two apart.
A teething baby tends to drool more than usual, may have slightly swollen or reddened gums, and is often comforted by chewing on a cold teething ring or a clean wet washcloth. If the head shaking is accompanied by these signs and your baby does not have a fever above what is typical for teething (mild, low-grade temperature at most), teething is a likely contributor. If the fever is higher or the baby seems genuinely ill rather than just uncomfortable, an ear infection is a better explanation and worth checking.