Skip to main content

Warning notification:Warning

Unfortunately, you are using an outdated browser. Please, upgrade your browser to improve your experience with HSE. The list of supported browsers:

  1. Chrome
  2. Edge
  3. FireFox
  4. Opera
  5. Safari

Plagiocephaly (flat head syndrome) in babies

Your baby might have plagiocephaly (sometimes known as flat head) if the side or back of their head appears flat.

This happens because your baby’s head is soft and can easily change shape.

Usually, any flattening can be stopped quickly if you encourage your baby to stop preferring one position or direction. For example, your baby might prefer sleeping on their right or looking in one direction.

Any head flattening should improve naturally as your baby gets older and the bones in their head gradually fuse together. This can happen up to the age of 5.

Some flattening is normal

Some flattening is a normal part of head shape and will be largely disguised by hair. Your baby’s flattened head will not cause pressure on their brain or developmental problems.

If your baby has a mild case of plagiocephaly, they do not need to see a physiotherapist. The condition will usually improve if you follow the advice on this page.

Only babies with serious cases of plagiocephaly are referred to a physiotherapist.

Causes of flat head

Your baby’s skull is more likely to flatten if your baby:

  • spends a lot of time asleep and in the same position
  • has tight neck muscles
  • does not lie on their tummy enough when they are awake, known as ‘tummy time
  • spends a lot of time in a car seat, making it hard for them to move freely
  • was born premature - this means their skull will be softer, and they might not have been able to be moved enough

Help stop your baby’s head flattening

You can help prevent plagiocephaly in your baby by changing the direction their head is turned each night as they sleep.

Always place your baby on their back to sleep as this reduces the risk of cot death.

How to help your baby's head shape

You can help your baby’s head to reshape correctly by encouraging them to do different actions.

For example, if their head is flattened on the right, you can encourage them to spend more time looking to the left by putting a toy on that side.

You can also do the following to correct the flattening:

  • make a habit of having tummy time, starting with several times a day for a few minutes each time and building up the time over several days
  • turn your baby’s head while they are asleep
  • turn your baby’s cot so that they look to the opposite side to see you
  • help your baby to prop themselves up by putting their elbows under their shoulders and using a rolled-up towel to help if needed
  • change the side of the head your baby lies on each time you put them down to sleep so they use different positions for sleeping
  • hold your baby against your shoulder on the opposite to normal, for example your right shoulder rather than your left
  • learning any necessary neck stretches for your baby from a physiotherapist

How long head flattening takes to improve

Your baby’s head shape should stop flattening and start improving as soon as you can encourage them to sleep, look and move both left and right.

Watch a video to find out more about plagiocephaly with Sheila Kiely, physiotherapy manager at Sligo University Hospital.

Plagiocephaly (flat head syndrome in babies)

Page last reviewed: 17 August 2021
Next review due: 17 August 2024

Slaintecare logo
This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 8.