This content is for educational purposes only and does not constitute medical advice, diagnosis, or treatment. For concerns related to your baby’s health, development, or sleep, or your own physical or mental wellbeing, always consult a qualified healthcare provider.
Most of the time, your baby’s body is doing exactly what it should. But there are certain patterns pediatric physical therapists and developmental specialists flag as worth paying attention to, especially in those early weeks and months when the window for early intervention is widest. None of these signs means something is definitely wrong, but all of them are worth mentioning to your pediatrician or a pediatric physical therapist sooner rather than later.
A strong preference for turning the head to one side
If your baby almost always looks to the right (or almost always to the left) and resists or seems uncomfortable turning the other way, this could be a sign of torticollis (a tightening of the sternocleidomastoid muscle on one side of the neck). Torticollis is usually first identified when the baby has a persistent head tilt or turn toward one side, and it can be congenital (present at birth) or acquired in early infancy.1 Without treatment, torticollis can lead to head flattening, delayed milestones, and postural imbalances, but early intervention with pediatric physical therapy can resolve it and prevent long-term complications.2
Also watch for a feeding preference on one side only (always wanting to latch or take a bottle from one particular angle), as this can be another sign of neck tension even when the head turn isn’t obvious.
A flat spot developing on the head
Flat head syndrome (also called positional plagiocephaly) most commonly happens when a baby sleeps with the head turned to the same side during the first months of life, causing a flat spot on one side or the back of the head.3 Most parents and caregivers notice the flattening at around 6 to 8 weeks old.4 It’s closely linked to torticollis: when a baby can’t comfortably turn their head both ways, pressure concentrates on one spot. According to the American Academy of Pediatrics, doctors should screen for signs of uneven posture at every well-child visit from birth through the first six months, and infants with uneven posture should be referred to a pediatric physical therapist for evaluation and treatment.5
Asymmetrical movement (using one side of the body more than the other)
Reaching, kicking, and tummy time skills should be consistent and symmetrical. If your baby’s head tilts to one side or they show a strong preference for using one arm, it’s a sign they should be seen by a pediatric physical therapist.6 Before age 3 or 4, babies shouldn’t have a dominant side. A preference at this stage is more likely a sign of strength, tone, or flexibility differences than true handedness.
Extremely floppy or extremely stiff muscle tone
Both ends of the muscle tone spectrum are worth flagging. Extremely floppy or stiff muscle tone, and an inability to hold the head with any control during tummy time by 3 months, are red flags.7 High muscle tone (hypertonia) doesn’t mean a baby is strong; it means their muscles are constantly in a more contracted state, which can make transitions and mobility harder.8 Signs of high tone can include an arched back, stiff legs, and difficulty being held in a curled position. Low tone (hypotonia) can look like a baby who feels unusually heavy or “melts” into you, with limited resistance when their limbs are moved.
Early “rolling” that looks uncontrolled
If your very young baby (before 3 months) seems to flip from their tummy to their back, it’s worth watching closely. This kind of early movement can be a symptom of disturbed tension distribution. Parents sometimes interpret it as an early milestone, when it’s actually an uncontrolled movement pattern resulting from abnormal muscle tension rather than intentional motor control.9
Persistent upset during tummy time
Some fussing during tummy time is completely normal (it’s hard work!), but if your baby consistently seems distressed, arches their back significantly, or is unable to briefly lift their head at all by 3 months, it’s worth getting eyes on it. An inability to hold the head up during tummy time by 3 months warrants evaluation by a pediatric physical therapist, who can assess muscle tone and recommend appropriate intervention.10
Consistently clenched fists after 2 to 3 months
Newborns naturally keep their fists closed, but by 2 to 3 months babies increasingly open their hands and bring them to their mouth. Persistent fisting after this age, especially if accompanied by stiff muscle tone or asymmetry, warrants evaluation.10
The bottom line
Early detection makes a real difference. Research has shown that the earlier a baby begins physical therapy, the better their outcomes will be and the shorter their treatment duration will be.11 If something feels off, even if you can’t quite name it, trust your instincts and bring it up at your next well-visit. You know your baby best.
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References
1. UPMC Children’s Hospital of Pittsburgh. “Torticollis.” https://www.chp.edu/our-services/plastic-surgery/conditions/torticollis
2. Strive Pediatrics. “Torticollis in Babies: Signs, Treatment, and Early Therapy.” https://www.strivepediatrics.com/all-blog-posts/torticollis-in-babies-signs-treatment-and-why-early-therapy-matters
3. Nemours KidsHealth. “Flat Head Syndrome.” https://kidshealth.org/en/parents/positional-plagiocephaly.html
4. Boston Children’s Hospital. “Plagiocephaly.” https://www.childrenshospital.org/conditions-treatments/plagiocephaly
5. American Physical Therapy Association / Choose PT. “Physical Therapy Guide to Torticollis.” https://www.choosept.com/guide/physical-therapy-guide-torticollis
6. Developmental Steps. “Milestones for Babies: The Red Flags Each Parent Should Know by 6 Months.” https://developmentalsteps.com/milestones-for-babies/
7. Nric-Ri. “Red Flags in Baby Development (0–12 Months).” https://www.nric-ri.org/red-flags-in-baby-development/
8. The Moving Peanut. “What Is Muscle Tone in Babies?” https://www.themovingpeanut.com/blog/muscle-tone-in-babies
9. Epozytywna Opinia. “Increased Muscle Tone in Infants.” https://epozytywnaopinia.pl/en/increased-muscle-tone-in-infants-symptoms-causes-exercises
10. Physical Therapy for Infants. “When to Consult a Physical Therapist: 12 Baby Development Signs to Watch for in Babies 0–4 Months.” https://www.physicaltherapyforinfants.com/tips/when-to-consult-physical-therapist-baby-development
11. Play at Home PT. “Effective Approaches to Torticollis Treatment.” https://playathomept.com/treating-torticollis/
