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. Congenital muscular torticollis (CMT) is typically characterized by the head tilting toward one side with rotation toward the opposite side, and it can be congenital (present at birth) or develop in early infancy.¹ Without treatment, torticollis can lead to head flattening (plagiocephaly), delayed milestones, and postural imbalances.² Early intervention with pediatric physical therapy is highly effective: treatment initiated before 1 month of age yields a 98% success rate, with the infant achieving near-normal range of motion by about 2.5 months of age.³ When treatment is delayed to 6 months or later, it can require 9 to 10 months of therapy with less success in achieving full range of motion.³
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 is not obvious.
A flat spot developing on the head
Positional plagiocephaly (flat head syndrome) is caused by persistent external pressure on one area of the skull and is the most common head shape abnormality in infants.⁴ The incidence has been estimated at 20% to 50% in infants under 6 months, and it is most commonly first noticed during the first 4 to 12 postnatal weeks.⁴ The infant’s rapidly growing head is most susceptible to deformation between 2 and 4 months of age.⁵ Plagiocephaly is closely linked to torticollis: 15% to 20% of infants with positional plagiocephaly have some degree of neck muscle imbalance, and infants who cannot comfortably turn their head both ways tend to develop concentrated pressure on one spot.⁴
The AAP recommends supervised, awake tummy time beginning soon after hospital discharge, increasing to at least 15 to 30 minutes daily by 7 weeks of age, as a key strategy for reducing the risk of positional plagiocephaly.⁶ Alternating the direction of the infant’s head during supine sleep and limiting time in car seats and other devices are also important preventive measures.⁵ˑ⁷ If a flat spot is developing, bring it up with your pediatrician. Physical therapy referral may be warranted, particularly if torticollis is also present.⁸
Asymmetrical movement (using one side of the body more than the other)
Reaching, kicking, and tummy time skills should develop symmetrically. Before 9 months of age, pediatricians should observe for any asymmetry of movement, persistent fisting, and lack of reaching, which may be signs of abnormal tone.⁹ Handedness is unusual before 18 months of age and may indicate asymmetry of tone and function on the opposite side.⁹ If your baby consistently reaches with only one arm or kicks more strongly with one leg, it is worth having a pediatric physical therapist evaluate them.
Extremely floppy or extremely stiff muscle tone
Both ends of the muscle tone spectrum are worth flagging. Hypotonia (low tone) may be defined as reduced resistance to passive range of motion or loss of postural control — a baby who feels unusually heavy or “melts” into you, with limited resistance when their limbs are moved.¹⁰ Hypertonia (high tone) does not mean a baby is strong; it means their muscles are constantly in a more contracted state, which can make transitions and mobility harder. Signs of high tone can include an arched back, stiff legs, scissoring of the legs, and difficulty being held in a curled position.¹¹ Both increased and decreased muscle tone are examination findings associated with motor disorders and warrant evaluation.¹¹
Early “rolling” that looks uncontrolled
If your very young baby (before 3 months) seems to flip from their tummy to their back, it is worth watching closely. According to the AAP, gross motor milestones that appear to be acquired excessively early or in an unusual sequence — such as rolling by arching the back at 1 month of age — may be driven by unusually strong primitive reflexes or tone abnormalities rather than intentional motor control.⁹ Parents sometimes interpret this as an early milestone, when it may actually be an uncontrolled movement pattern. Early atypical rolling is one of the signs pediatricians should watch for during developmental surveillance before 9 months.⁹
Persistent upset during tummy time
Some fussing during tummy time is completely normal — it is 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 is worth getting eyes on it. An inability to hold the head up during tummy time by this age warrants evaluation by a pediatric physical therapist, who can assess muscle tone and recommend appropriate intervention.
Consistently clenched fists after 3 months
Newborns naturally keep their fists closed — fisting is a predominant hand posture in about 75% of newborns.¹² By around 3 months, babies increasingly open their hands and bring them to their mouth. One study found that the thumb-in-fist posture resolved at a mean age of 1.5 months, and no cases persisted beyond 7 months.¹³ Persistent fisting and hand fisting are among the six signs agreed upon by parents and pediatricians to expedite diagnostic referrals for cerebral palsy.¹⁴ The AAP also identifies persistent fisting before 9 months as a sign of possible abnormal tone that warrants developmental surveillance.⁹ If your baby’s fists remain consistently clenched after 3 months, especially if accompanied by stiff muscle tone or asymmetry, bring it up with your pediatrician.
The bottom line
Early detection makes a real difference. A Cochrane review of early developmental intervention programs found that early intervention may improve motor outcomes in infancy compared with standard follow-up.¹⁵ For torticollis specifically, the difference between early and late treatment is dramatic: intervention before 1 month of age yields a 98% success rate, while intervention at 6 months or later requires significantly longer treatment with less success.³ Providing pediatricians with standardized screening techniques has been shown to increase the frequency of diagnosis, improve comfort with screening, and decrease the age at diagnosis.⁸
If something feels off — even if you cannot quite name it — trust your instincts and bring it up at your next well visit. You know your baby best.
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.
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References
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2. Goodstein MH, Stewart DL, Keels EL, Moon RY. Transition to a Safe Home Sleep Environment for the NICU Patient. Pediatrics. 2021;148(1):e2021052046.
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4. Dias MS, Samson T, Rizk EB, Governale LS, Richtsmeier JT. Identifying the Misshapen Head: Craniosynostosis and Related Disorders. Pediatrics. 2020;146(3):e2020015511.
5. Darrow HJ, Carman KA, Wheeler V. Sudden Infant Death Syndrome: Common Questions and Answers. American Family Physician. 2025;111(2):164-170.
6. Moon RY, Carlin RF, Hand I. Evidence Base for 2022 Updated Recommendations for a Safe Infant Sleeping Environment to Reduce the Risk of Sleep-Related Infant Deaths. Pediatrics. 2022;150(1):e2022057991.
7. Aarnivala H, Vuollo V, Harila V, et al. The Course of Positional Cranial Deformation From 3 to 12 Months of Age and Associated Risk Factors: A Follow-Up With 3D Imaging. European Journal of Pediatrics. 2016;175(12):1893-1903.
8. Carlton L, Lohman E, Elmendorf E, et al. Screening for Torticollis and Plagiocephaly: The Role of the Pediatrician. Medicine. 2025;104(49):e46259.
9. Davis BE, Leppert MO, German K, Lehmann CU, Adams-Chapman I. Primary Care Framework to Monitor Preterm Infants for Neurodevelopmental Outcomes in Early Childhood. Pediatrics. 2023;152(1):e2023062511.
10. Morton SU, Christodoulou J, Costain G, et al. Multicenter Consensus Approach to Evaluation of Neonatal Hypotonia in the Genomic Era: A Review. JAMA Neurology. 2022;79(4):405-413.
11. Noritz G, Davidson L, Steingass K. Providing a Primary Care Medical Home for Children and Youth With Cerebral Palsy. Pediatrics. 2022;e2022060055.
12. Faridi MM, Rath S, Aggarwal A. Profile of Fisting in Term Newborns. European Journal of Paediatric Neurology. 2005;9(2):67-70.
13. Jaffe M, Tal Y, Dabbah H, et al. Infants With a Thumb-in-Fist Posture. Pediatrics. 2000;105(3):E41.
14. Novak I, Jackman M, Finch-Edmondson M, Fahey M. Cerebral Palsy. Lancet. 2025;406(10499):174-188.
15. Orton J, Doyle LW, Tripathi T, et al. Early Developmental Intervention Programmes Provided Post Hospital Discharge to Prevent Motor and Cognitive Impairment in Preterm Infants. Cochrane Database of Systematic Reviews. 2024;2:CD005495.
