Flat Head Syndrome (Plagiocephaly): Causes, Prevention & Treatment

You've been doing everything right — back to sleep for every nap and every night. But now you've noticed the back of your baby's head looks a little flat on one side, or perhaps flatter overall. Welcome to the world of positional plagiocephaly — one of the most common concerns among UK parents with young babies.

What is flat head syndrome?

Positional plagiocephaly refers to a flattening on one side of the back of the head, often accompanied by the ear on the flat side being pushed forward. Brachycephaly is flattening of the entire back of the head, making it look wider and higher than normal.

Both are caused by the same thing: pressure on the same part of the skull over time when the skull is at its most soft and malleable (the first few months of life).

Why has it become more common?

The "Back to Sleep" campaign, launched in the 1990s, dramatically reduced SIDS deaths — a huge success. However, the side effect has been an increase in positional flat head syndrome, since babies spend significantly more time on their backs than previous generations.

Is it dangerous?

Pure positional plagiocephaly is primarily a cosmetic concern — it does not affect brain development. The brain continues to grow normally inside the skull. However, severe cases can cause facial asymmetry, and in some babies, a tight neck muscle (torticollis) is the root cause and needs treatment.

Causes and risk factors

• Always turning head to the same side (possible torticollis)
• Spending long periods in car seats, bouncers, or swings (reduces repositioning)
• Premature birth (skull softer for longer)
• Multiple births (less womb space for repositioning)
• First-born babies (womb space more constrained)

Prevention and repositioning

The earlier you start repositioning, the better. The skull is most responsive before 4–5 months.

Tummy time (the single most important intervention)

Time on the tummy when awake and supervised:

• Relieves pressure on the back of the skull entirely
• Builds the neck, shoulder, and core strength babies need for rolling and sitting
• Aim: Start with 2–3 sessions per day from birth, build to 30 minutes total daily by 3 months

Head repositioning during back sleep

• Alternate which end of the cot baby's head is at each sleep — they tend to turn toward activity
• Encourage baby to look the other direction by placing interesting things (mobiles, light sources) on the non-flat side
• When holding and carrying, try to vary which shoulder baby rests their head on

Reduce time in "containers"

Car seats are non-negotiable for car journeys, but try to:

• Take baby out of the car seat as soon as you arrive somewhere
• Use a pram rather than leaving baby in a car seat on a pram frame for long walks
• Limit time in bouncers and swings

Feeding position

If breastfeeding, alternate which arm baby lies in for each feed.

When to see a doctor

See your GP or health visitor if:

• Flat area is noticeable before 4 months and isn't responding to repositioning
• Baby consistently turns head to one side only (could indicate torticollis)
• You notice facial asymmetry — one eye or ear noticeably higher than the other

Your health visitor will assess the shape at developmental reviews. Your GP can refer to a paediatric physiotherapist or specialist clinic if needed.

Physiotherapy

If a tight neck muscle (torticollis) is found, a paediatric physiotherapist will teach you gentle stretching exercises to do at home. This typically resolves within 3–6 months with consistent work.

Helmet therapy

Cranial remoulding helmets (often called DOC bands in the UK) are sometimes recommended for severe cases diagnosed before 6 months. They work by providing a tight-fitting shell that allows the skull to grow into a more symmetrical shape.

The NHS rarely funds helmet therapy; private treatment costs typically £2,000–£3,500 and involves wearing the helmet 23 hours a day for 3–6 months.

Most mild to moderate cases resolve with repositioning alone — don't feel you need to immediately pursue helmet therapy. A good physiotherapist assessment is the right first step.

The good news

The vast majority of flat head cases improve significantly with consistent repositioning and tummy time. Babies are incredibly resilient, and the skull continues to fill in throughout the first two years of life.

Take photos regularly — it's often hard to see gradual improvement day-to-day, but comparing photos from a month apart tells a clear story of progress.