Babies can sometimes develop a flattened head, known as flat head syndrome, as a result of long periods lying in the same position.
Flat head syndrome is common and affects around 1 in 5 babies. General development is not affected by flat head syndrome, and your baby will not experience any pain or other symptoms because of the condition.
In most cases there is no cause for concern and their head shape will improve over time as they develop. You should speak to your health visiting team or GP if you’re concerned, or if you think your baby is having trouble moving their head.
Mild flattening will usually improve over time, but it can take a couple of months to notice any improvements.
Helmets, headbands and mattresses designed to relieve head pressure are not recommended and can be uncomfortable and distressing for your baby.
There are two main types of flat head syndrome, plagiocephaly and brachycephaly.
Babies with plagiocephaly may have:
- Flattened heads on one side, which may look asymmetrical. Their heads can look like a parallelogram from above.
- Ears that appear to be misaligned.
- Foreheads which seem to be bulging on the flattened side.
In brachycephaly:
- The rear of the head is flattened, this might cause the head to widen
- Occasionally, the forehead appears to bulge.

Your baby will have their head circumference (size) measured at birth and at their 6-8 week baby check. If there are any worries regarding head shape or size, you can discuss this with your health visiting team and a plan may be made to take further measurements.
You should also speak to your GP or health visiting team if your baby:
- seems to have an unusually large head. For example their head is too big to fit hats for their age group and/or being unable to fit their head through a babygro that fits their body.
- has a bulging fontanelle (soft spot).
- has eyes looking downwards (sunsetting)
- Your baby has difficulty turning their head or has a strong preference for turning their head to one side.
- Your baby has an unusual head shape or has very prominent uneven ridges which have not got better or have got worse, despite repositioning suggestions described above.
- has prominent veins on their head, alongside one or more of the above symptoms
- Very occasionally, a flat head can be caused by the skull plates forming your child’s head joining together too early. There is a medical name for this, craniosynostosis, and it requires specialist review and management.
Useful links
NHS – Plagiocephaly and brachycephaly