Understanding Plagiocephaly (Flat Head Syndrome)
- Dec 7
- 6 min read
Updated: 2 hours ago
If you’ve noticed a flat spot on your baby’s head (often called “flat head syndrome”), you’re not alone.
Up to 40% of infants show some degree of plagiocephaly today. This is partly due to the “Back to Sleep” (now “Safe to Sleep”) campaign. This campaign has been hugely successful, cutting infant mortality by 50% in the UK and up to 81% in the UK (Lullaby Trust). So even if your baby has plagiocephaly, always place them on their back to sleep (or in safe co sleeping).
Even with plagiocephaly, the advice is to always follow Safe to Sleep guidelines to protect against SIDS, while implementing awake-time positioning strategies for prevention and correction.
Let’s walk through what plagiocephaly is, why it happens, how to spot it, and what you can do to help.
What is Plagiocephaly?
Plagiocephaly is a misshapen, asymmetrical, or flattened head in a baby. It happens due to ongoing asymmetrical pressure on the soft and flexible skull, often because the baby has a side preference or tight neck muscles (torticollis).
Most cases are positional (the skull bones are flexible, not fused), and many babies improve with early intervention.
What Are the Types of Flat Spots?
The location and severity of the flat spot depends on where and for how long there has been pressure on the skull. Babies can have a combination of types, which is why a thorough assessment is needed to give tailored treatment strategies.
Does It Impact Development?
Positional plagiocephaly does NOT impact brain development. It does not itself cause developmental delay, but research shows it can be a marker for a higher risk of motor delays (Martiniuk et al., 2017).
For example, a baby with delayed or difficult motor skills (like lifting their head or rolling) may spend longer periods on their skull, which can contribute to flattening. An example would be a baby with an underlying medical condition that may or may not yet be diagnosed.
Clinically, we often see flat head shapes impacting aspects of sensory and motor development. This is because a babies head position directly impacts some sensory systems (vision, vestibular) and how they move (primitive patterns, reflexes and where gravity is taking them). A common example would be a baby always looking to the left may find their head to the right side disorientating (because their inner ear and vision has not spent time there), they might also use their right hand more (because it’s been more in their field of vision, and impacted by reflexes) and they may prefer or only roll to their left (because head movement drives body movement). This is a “knock on” effect of head position which should improve with treatment.
This is why it is worth checking in with a Paediatric Physiotherapist. We assess every baby for all contributing factors, provide support for difficulties with early intervention, and make onward referrals for further investigations when needed.
How Does It Happen?
Babies spend a lot of time sleeping in their first months – sometimes up to 20 hours a day. The combination of prolonged back-lying and side preference can lead to flattening. Other contributors include:
Torticollis
A strong head turn preference to one side
Limited tummy time or variety in positioning during awake time (e.g., due to reflux)
Long periods in car seats, bouncers, or swings
Intrauterine position (position or limited space in the womb)
Multiple births (twins, triplets)
A diagnosis or neurodevelopmental difference which impacts head position, motor or sensory development (eg. hearing or vision impairments)
Premature birth (preterm babies are at risk of developing scaphocephaly and other flat spots as their skulls are softer at birth and during their NICU stay)
NICU stay or medical conditions (babies may have longer periods on the cot or have limited positioning options due to medical instability, lines, or devices)
Remember – these are risk factors, not causes you’ve created.
How Can I Spot It?
Look at your baby’s head from above (“bird’s eye view”) or take a photo. I recommend doing this monthly until they are 4 months old – after this age, flat spots are less likely to develop unless there is a movement delay. You can use my free home head and neck check here.
How Can I Prevent It?
The most important factor is to include a variety of positions in your newborn’s day:
1. Varied floor positions – tummy time (on your chest counts for newborns), side-lying, and back time
2. Varied carry positions – switch feeding sides, alternate which shoulder you carry them on, and change their head orientation in the sling, carrier, bassinet, or crib. In the crib, you can alternate which side you’re on for sleep each night by switching their position.
3. Limit “container” time – car seats, bouncers, and swings should be limited to ~30 minutes daily (not including necessary travel)
4. Monitor head turn preference, neck tightness, or flat spots – ensure your baby can turn both ways and check their head shape regularly
5. Babies born preterm and those with lengthy NICU stays - good positioning and developmental care (including lots of parent cuddles!) should be standard care from the NICU team. You should be supported to feel confident with this, and what to do once you go home too.
How Can I Treat It?
Most flat spots resolve well with growth and movement off the area. The main principles of treatment are:
Encouraging your baby to turn to the other side
Limiting time on the flat spot
Maximising time on the prominence areas to remould the shape
Supporting motor and sensory progress so babies can quickly move off the flat area, and prevent asymmetrical motor patterns or sensory effects
Passive stretching alone is not evidenced and should only be used as a part of a more specific treatment program
Early physiotherapy is highly effective – starting treatment before 3–4 months is ideal.
There are endless tips, videos, and guides online – it can be overwhelming, and even if you’re doing 10 things, you might be missing the one thing that targets your baby’s flat spot. It is far easier and more effective to have a Paediatric Physiotherapist provide an evidence-based, tailored program.
What About Head Shape Pillows or Positioners?
These are not recommended. They’re not safe for sleep under UK guidelines, there’s no robust evidence they work, and they don’t address the root cause. In some cases they even restrict movement, which can make flattening worse.
What About Helmet Therapy?
Helmet therapy with a cranial remoulding orthosis is controversial, and usage varies across countries.
In Australia and the UK, helmets are not recommended due to lack of evidence and are not publicly funded.
In the US, helmets are more commonly used.
Evidence shows helmets are no better than physiotherapy for mild cases treated before 4–6 months. They may be considered in severe cases, older babies, or those who have not responded to physiotherapy.
You can read the NHS statement about helmets for plagiocephaly here: NHS Helmet Guidance
My recommendations around helmets:
The fastest, best outcomes come from treatment started before 3–4 months with a physiotherapist experienced in plagiocephaly.
If your babies head shape is severe or persistent enough that you are considering a helmet, they should also see a Medical Doctor (eg. GP or Paediatrican) AND Paediatric Physiotherapist.
Helmets will not treat the underlying cause of flattening, so they should be accompanied by physiotherapy.
Do consider private physiotherapy if public healthcare is inaccessible, wait times are long, or a second opinion is desired.
When to See a Health Professional
After 2 weeks of trying home strategies with no improvement
Signs of neck tightness or torticollis
Strong head turn or side preference
Flattening persists past ~6 weeks
Head shape seems to worsen
Head shape doesn’t relate to where baby lies
Signs of developmental delay or difficulty
Unusual lumps, ridges, or any concerns about their soft spot (either very large or seems closed within the first few months)
Tummy time or head turning is difficult
Asymmetry in ears, forehead, or face
Reassurance or guidance needed
“Wait and see” is not recommended – early intervention is evidenced, easier on the whole family and has a shorter treatment time.
If you're UK resident you can book in with April Baby Physio below.
What About Craniosynostosis?
Craniosynostosis is completely different from positional plagiocephaly. It is not related to positioning.
It is rare, occurring when one or more skull sutures close prematurely, causing a fixed, abnormal head shape. Unlike positional plagiocephaly, it can impact brain growth. It is dangerous not to seek medical care for this and it typically requires surgery and a helmet to allow the skull and brain to grow appropriately. Signs include a ridge along a suture, a head shape that doesn’t change with repositioning, unusual facial asymmetry or a soft spot which completely closes very early. Your doctor or paediatric physiotherapist should always assess for this when evaluating a flat head.
The Takeaway
Plagiocephaly is typical, common, and treatable. Monitoring head shape and motor development, using early positioning strategies, and seeking physiotherapy when needed usually ensures excellent outcomes.
Blanket guidance like “do more tummy time” or “wait and see” is often not enough, can delay treatment, and parents deserve more support. Seek a paediatric physiotherapist if home strategies have not resolved the flat spot in a couple of weeks.
Always follow Safe to Sleep guidelines to protect against SIDS, while implementing awake-time positioning strategies for prevention and correction.
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