Flat Head (Positional Plagiocephaly)
Why some babies develop a flat spot on the head, how to prevent it, and when to seek help.
- Last reviewed
- Sources cited
- 4 sources
- Author
- Dr Jubal John, FRACP
- Category
- medical guides
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Take-home
A flat spot on your baby’s head is common and does not affect brain development or intelligence. It happens because the skull is soft and takes the shape of whatever pressure it gets. Tummy time when awake, varied positions, and always placing baby on their back to sleep work together to prevent and fix it.
A flat spot is fixable. SIDS is not.
A baby always sleeps on their back, every sleep, every nap. We prevent and treat flat spots while keeping safe sleep, never the other way around. See safe sleep for the full Red Nose principles; this guide assumes that baseline.
What it looks like
Babies’ skulls are soft and made up of bony plates that grow as the brain grows. If a baby rests on the same spot day after day, that spot can flatten. The shape parents and clinicians look for falls into three named patterns:
None of these affect how your baby’s brain develops. They are changes in head shape only, and usually correct over the first months with simple positioning measures. The fourth shape above (scaphocephaly, long and narrow) is mostly seen in babies who spent time in NICU lying on alternating sides, and usually self-corrects after discharge.
Why it happens
Common reasons
- Back sleeping (still the safest position, don’t change this)
- Lots of time in a car seat, bouncer, or swing
- Being born early (softer skull)
- Twin or triplet pregnancies (crowded in the womb)
- Torticollis: a tight neck muscle on one side so the baby always looks the same way
- Not enough awake tummy time
How to check your baby’s head shape
- Look at your baby’s head from above (bird’s-eye view): compare both sides.
- Check if one side is flatter than the other.
- Look at the ears, is one pushed forward?
- Look at the forehead, is one side more prominent?
- Take a weekly photo so you can track changes.
Head shape is worth mentioning at your routine 6-week, 4-month, and 8-month MCH checks, or sooner if you are worried.
Tummy time: the most important prevention
Supervised tummy time while your baby is awake helps prevent flat spots, strengthens neck and shoulder muscles, and supports rolling, crawling, and sitting.
How much tummy time?
- Newborn: 1–3 minutes at a time, several times a day (on your chest counts)
- 1–2 months: aim for 20–30 minutes spread across the day
- 3–4 months: around 40–60 minutes across the day
- 5–6 months: up to 60–90 minutes across the day
Making tummy time work
- Start short and build up, crying is your baby telling you it is enough for now
- Get down on the floor face-to-face with your baby
- Use a mirror, toy, or sibling to keep their interest
- Try it after nappy changes when they are awake and happy
- On your chest (reclined) counts, and is a lovely way to start
- The Raising Children Network “Tummy time for babies: in pictures” guide walks through how
Positioning ideas for every day
- Alternate the end of the cot your baby’s head rests on each night
- Vary the arm you use to feed (swap sides even when bottle-feeding)
- Minimise time in car seats and bouncers when not actually travelling
- Carry your baby upright or in a carrier or sling when awake
- Change the view: move the cot or where you put the change mat, so baby looks different ways
When to see your doctor
Green — usually fine
Mild flat spot, improving
- Reshape by gentle position changes and more tummy time
- Review at your next MCH check
Amber — be alert
Moderate or not improving by 4 months
- Book a visit with your GP, MCH nurse, or paediatrician
- Physio can help if torticollis (neck tightness) is present
Red — act now
See a doctor promptly if:
- The head shape is very unusual (not just a flat patch)
- There is a hard ridge along the skull lines
- Your baby can only turn their head one way
- You are worried about your baby’s development
Treatment options
Treatment depends on age and how noticeable the flattening is. Earlier is easier.
0–6 months: repositioning and tummy time
Usually enough on its own. Physiotherapy helps if there is torticollis.
4–12 months: helmet therapy (only for some)
For moderate to severe plagiocephaly that has not responded to repositioning, a custom-made helmet can help. It is worn 23 hours a day for 3–6 months and only fitted by a specialist after assessment. It is most effective between 4 and 8 months and is not needed for most babies. Helmets are not currently routinely funded in Australia, discuss cost and benefit with your paediatrician.
6 months and older: natural improvement
Once your baby is sitting, rolling, and spending less time on their back, the head shape usually improves on its own.
What plagiocephaly does not affect
- Brain development or intelligence
- Reaching developmental milestones
- Personality
- Future health, hair growth, or hat fitting
A note on craniosynostosis
Very rarely, an unusual head shape is caused by craniosynostosis: where the bony plates fuse too early. This is not the same as plagiocephaly and needs different treatment. Signs that should trigger a doctor’s review include a hard ridge along the skull lines, a head that does not round out, or a shape that gets worse rather than better. Your doctor can tell the difference.
Summary
Key points to remember
- A flat spot is common, harmless, and largely preventable, and it doesn’t affect brain development
- Always place your baby on their back to sleep, it saves lives
- Awake tummy time is the single most helpful habit
- Change positions, carriers, and the angle of the cot daily
- See your GP or paediatrician if the shape is not improving by 4 months