Babies scrunch their faces for a wide range of reasons, from reflexes and sensory reactions to communication and normal brain development. Most of the time, it’s completely harmless. In the first few months of life, your baby’s nervous system is still maturing, and facial scrunching is one of the ways their body processes the world, practices muscle control, and signals needs.
Reflexes Drive Many Early Facial Movements
Newborns come wired with a set of automatic muscle reactions that can produce all kinds of face scrunching. The rooting reflex, for example, kicks in when something touches your baby’s cheek. They’ll turn toward the touch and start making sucking motions, which can look like a dramatic face scrunch. The sucking reflex does something similar whenever the area around the mouth is stimulated. These reflexes are present from birth (rooting actually develops in utero around 24 weeks) and typically fade by 3 to 4 months as your baby gains voluntary control over their movements.
During this early window, much of what looks like an expression isn’t really an expression at all. It’s an involuntary muscle response firing in reaction to something touching or stimulating your baby’s face.
Taste and Smell Trigger Specific Reactions
Even hours-old newborns produce distinct facial responses to different tastes. Sweet flavors cause facial relaxation and sucking. Sour tastes trigger lip pursing. Bitter tastes produce mouth gaping. All three non-sweet taste categories share the same scrunched-up upper and mid-face components, that classic “disgusted” look, but the lower face responds differently depending on the specific taste. Research on neonatal taste responses has shown that babies can distinguish sour from bitter from salty from sweet right from birth.
So if your baby scrunches their face during breastfeeding or after tasting something new, they may genuinely be reacting to a flavor. By around 3 months, babies develop a clear expression of disgust in response to sour tastes or loud sounds, marking one of their earliest purposeful facial expressions.
Sensory Overload Causes Scrunching
Babies have limited ability to filter sensory input. Too much noise, bright light, crowded spaces, strong smells, or even colorful surroundings can overwhelm them. When that happens, face scrunching is often one of the first visible signs, sometimes followed by fussiness, crying, or turning away. Newborns are especially sensitive to light because their pupils don’t constrict as efficiently as an adult’s, so you might notice scrunching when moving from a dim room to a bright one or stepping outside.
If your baby seems to scrunch up in busy environments, the simplest fix is moving to a quieter, darker space. That alone often resolves the reaction within a few minutes.
Sleep Twitches Are Normal and Important
If you’ve noticed your baby’s face twitching, grimacing, or scrunching while asleep, that’s almost certainly happening during REM sleep. Infants spend far more time in REM sleep than adults do, and during this stage, motor areas in the brain generate brief, jerky movements in the face and limb muscles. These movements can look startling: eyebrows furrowing, lips puckering, little grimaces flickering across a seemingly peaceful face.
These twitches aren’t random glitches. Researchers at the University of Tübingen describe them as a form of “self-stimulation” that feeds sensory information back to the developing brain. This process helps tune the connections between sensory and motor systems during a time when the brain is disconnected from outside input. In other words, your baby’s face is practicing while they sleep, and that practice helps wire their brain for more coordinated movement later on.
Communication Before Words
Before babies can talk, or even gesture reliably, their face is their primary communication tool. Hunger, gas, tiredness, discomfort, and frustration all produce scrunched or tense facial expressions. A scrunched face paired with rooting or hand-to-mouth movements usually signals hunger. A red, scrunched face with drawn-up knees often points to gas or digestive discomfort. A scrunched face with eye rubbing or yawning typically means fatigue.
By about 2 months, babies start smiling spontaneously at things they find pleasant, and the shift from involuntary to intentional expression accelerates from there. By 5 months, babies can match the emotional expressions of other infants, recognizing the difference between happy and frustrated faces paired with corresponding voices. This means the facial expressions you see becoming more varied and purposeful over those first months reflect genuine leaps in social and emotional development.
When Face Scrunching May Be a Concern
In rare cases, repetitive, rhythmic face or body scrunching can be a sign of infantile spasms, a type of seizure that typically appears between 3 and 12 months. These are distinct from normal scrunching in several important ways. During a spasm, the body stiffens suddenly. The back may arch, and the arms, legs, and head may bend forward. Sometimes the signs are subtler: just the eyes rolling up or a small abdominal crunch. The baby often looks surprised and may briefly stare.
The key difference is the pattern. Infantile spasms come in clusters, with each spasm lasting less than a second but repeating every 5 to 10 seconds in a series. They happen most often just after a baby wakes up and rarely during sleep. Between spasms, the baby appears fine, which can make them easy to dismiss. Parents may also notice a loss of developmental skills the baby had already learned, like rolling over, sitting, or babbling, along with fewer social smiles and increased fussiness or unusual quietness.
The American Academy of Pediatrics uses the acronym STOP to help parents recognize infantile spasms: See the signs (clusters of sudden, repeated, uncontrolled movements like head bobs or body crunching), Take video, Obtain a diagnosis, and Prioritize treatment. If the scrunching you’re seeing is repetitive, clustered, and happening right after waking, capturing it on video and sharing it with your pediatrician is the most useful step you can take.