Preventing Flat Spots on Baby's Head (Plagiocephaly)
The short answer
Flat spots on a baby's head (positional plagiocephaly) are very common because newborn skulls are soft and malleable. Prevention strategies include regular tummy time when awake, alternating head position during sleep, and minimizing time in car seats and bouncers when not traveling. Most mild flat spots improve on their own as baby grows.
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By Age
What to expect by age
A baby's skull is made of soft, flexible bones that can become flattened from sustained pressure in one position. Since babies must sleep on their backs for safety, some flattening is common. Prevention strategies from birth: alternate which direction baby's head faces during sleep (babies tend to look toward the room or light, so alternate which end of the crib their head is at), provide supervised tummy time starting from day one (even a few minutes several times a day), alternate which arm you use for feeding and holding, and limit time in car seats, swings, and bouncers when baby is not traveling. If baby has a strong head-turning preference, address it early with repositioning.
This is when flat spots most commonly develop and become noticeable. Increase tummy time gradually, aiming for 15-30 minutes total per day by 2 months. When baby is on their back, use toys and your voice to encourage looking in both directions. Your pediatrician will monitor head shape at well-visits. If a flat spot is developing, they may recommend increased repositioning, tummy time, or evaluation for torticollis, which is a common contributing factor.
As baby gains head control and spends more time upright, flat spots often begin to improve naturally. If a significant flat spot has not improved with repositioning by 4-6 months, your pediatrician may discuss referral for a cranial molding helmet. Helmet therapy is most effective between 4-8 months when the skull is still rapidly growing and most malleable. Not all flat spots require a helmet; many improve on their own.
Most mild to moderate flat spots continue to improve as baby spends more time sitting, crawling, and upright. Skull growth slows after 12 months, so significant improvements from repositioning alone become less likely. Helmet therapy, if needed, is typically completed by 12 months. Hair growth also helps camouflage remaining mild asymmetry. Long-term outcomes are excellent for the vast majority of children.
What Should You Do?
When to take action
- Mild flattening on one side or the back of the head
- Flat spot improves as baby increases tummy time and upright play
- Baby has no positional preference or torticollis contributing to the flat spot
- You notice a flat spot developing on one side or the back of the head
- The flat spot seems to be worsening despite repositioning
- Baby has a strong head-turning preference that may be contributing to the flat spot
- Severe or rapidly worsening head shape asymmetry
- Head shape changes with a bulging fontanelle, vomiting, or irritability, which could indicate increased intracranial pressure rather than positional flattening
- Concern that the skull sutures may be fusing prematurely (craniosynostosis): a ridge along the skull or abnormal head shape present at birth
Sources
Related Resources
Trust your instincts. If something feels wrong, reach out to your pediatrician.
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Related Physical Concerns
Baby Prefers One Position (Positional Preference)
Many newborns develop a preference for turning their head to one side, which is common and often resolves with simple repositioning strategies. However, a persistent preference may indicate torticollis (tightness in neck muscles), which responds well to stretching exercises and physical therapy when addressed early.
When to Start Tummy Time
Tummy time can and should start from day one. The AAP recommends supervised tummy time from the first day home. For newborns, this can be as simple as placing baby on your chest while you recline, or brief sessions on a firm surface for 1-3 minutes several times a day. Tummy time is essential for developing head control, strengthening muscles, and preventing flat spots.
Safe Sleep Position for Newborns
The safest sleep position for babies is on their back, on a firm flat surface, for every sleep. This recommendation from the AAP significantly reduces the risk of SIDS and sleep-related deaths. Always place your baby on their back until they can roll both ways independently.
My Baby Seems to Use One Side More Than the Other
Babies should use both sides of their body fairly equally during the first 18 months of life. While slight preferences can be normal, a consistent pattern of favoring one side - using one arm much more than the other, crawling with one leg dragging, or turning the head predominantly one way - should always be discussed with your pediatrician. Early identification of asymmetry leads to the best outcomes.
My Baby Only Army Crawls
Army crawling (also called commando crawling) is a completely valid and normal way for babies to move. Many babies army crawl for weeks or even months before transitioning to hands-and-knees crawling, and some skip hands-and-knees crawling entirely. What matters is that your baby is independently mobile and exploring their environment.
One Side of My Baby's Body Moves Differently
Babies should generally use both sides of their body equally. If one side consistently moves differently, is weaker, stiffer, or less coordinated, this warrants evaluation. Asymmetric movement can indicate hemiplegia (cerebral palsy affecting one side), brachial plexus injury, or other neurological conditions that benefit from early therapy.