Flat head syndrome in babies: prevention, helmets and red flags

Many babies develop a flat spot on the back or side of their head in the first few months, because their skull is soft and they spend a lot of time lying down. It looks worrying, but the NHS says it doesn't affect a baby's brain or development and usually gets better as they grow. The fix is never to change how your baby sleeps: keep them on their back for every sleep, and shift the pressure around while they're awake with tummy time, head-turning play and less time in seats. A few signs, such as a head that's always tilted or an unusual head shape from birth, are worth having checked.

What is flat head syndrome?

Flat head syndrome is the everyday name for a positional skull deformity, a change in head shape caused by pressure on one area of a soft skull. There are a few patterns:

The AAP's guide to positional skull deformities describes all three and says they do not affect brain growth or intellectual development. The Royal Children's Hospital Melbourne (RCH) agrees they don't affect brain growth, but notes that if left untreated, a flat spot may make the face and head grow a little unevenly. Red Nose in Australia says flat spots are usually reversible and rarely need significant medical or surgical treatment.

The AAP suggests checking your baby's head after a bath, when their hair is wet. Looking from above, the back of the head should be evenly round, the ears level, and the forehead balanced.

How do flat spots develop?

A newborn's skull is made of soft bony plates that haven't joined yet, so steady pressure in one place can change its shape. The AAP says some start in the womb or birth canal, but they more often develop in the first 4 to 12 weeks, before babies can sit up or move on their own. By 6 months, many babies turn their heads more freely.

Common causes, from the NHS, AAP and RCH:

• lying with the back or side of the head pressed on the mattress for long periods
• a favorite head position, such as always looking towards a window or a parent
• feeding or being carried on the same side every time
• tight neck muscles (torticollis), which make it hard to turn the head
• being a twin or triplet, or cramped in the womb
• being born prematurely, with softer bones and long spells lying in hospital
• a long or assisted birth; the RCH says moulding from birth often settles quickly
• lots of time in car seats, bouncers, swings and other seats

NICHD Safe to Sleep in the US also names spending time in a car seat or carrier too often, or for long periods.

Why does my baby still need to sleep on their back?

Because back-sleeping is what protects your baby from sudden infant death syndrome (SIDS), and flat spots are a cosmetic issue that can be managed while they're awake. The NHS says not to change your baby's sleeping position, because they should always sleep on their back to reduce the risk of SIDS. NICHD says the back is the safest position for all babies until they're 1 year old, for naps and at night, and that flat spots from back-sleeping are usually not dangerous and typically go away once babies start sitting up.

Keep every sleep safe:

• on their back for every sleep, day and night
• on a firm, flat, level mattress in their own crib or bassinet
• nothing soft or loose in the crib, and their head and face uncovered
• in your room for at least the first 6 months, day and night, in a smoke-free home

Australia's Red Nose's head-shape advice is to always place your baby on their back to sleep and never on their front. The Lullaby Trust says that once your baby can roll both ways on their own, they can find their own position, though you should still put them down on their back. See safe sleep for the full checklist and rolling over for what to do when they start to roll.

How can I prevent or improve a flat spot?

The same steps prevent a flat spot and help one that's already there. Australia's Red Nose says the most common treatments are the same as the prevention strategies.

1. Give plenty of supervised tummy time. Australia's Red Nose calls awake, supervised tummy time one of the most effective ways to reduce the risk. The AAP's back-to-sleep, tummy-to-play guide suggests starting with 3 to 5 minutes, 2 to 3 times a day, and working up to 15 to 30 minutes a day by 7 weeks. For a baby who already has a flat spot, the AAP's skull deformity guide suggests gradually working up to an hour a day in several short sessions. Never leave your baby alone on their tummy. See tummy time for positions and ideas.
2. Vary their head position when they're awake. The NHS suggests moving toys and mobiles so your baby turns their head both ways while lying on their back. The RCH suggests play on their side, on their tummy and face to face.
3. Alternate which way they face at sleep. Australia's Red Nose, the RCH and the AAP suggest alternating your baby's head position when you lay them down, or putting them at different ends of the crib. Babies like to look at windows, lights and people, so swapping ends makes them turn the other way to see the same thing.
4. Swap sides for feeds and carrying. The NHS, RCH and AAP all suggest changing the side you feed and carry on. Australia's Red Nose suggests holding your baby in your left arm for one feed and your right arm for the next, and the RCH suggests swapping bottle-feeding sides too, even if one side feels less natural.
5. Limit time in seats when you're not traveling. The AAP says too much time in a car seat, bouncy seat, swing or other carrier puts pressure on the back of the head. The NHS says to take your baby out of the car seat or stroller as soon as you get where you're going, and Australia's Red Nose says not to keep your baby in a seated position for long periods. The WHO recommends babies aren't restrained for more than 1 hour at a time in a stroller, high chair or carrier.
6. Hold your baby upright. The RCH suggests upright cuddles, a sling, or carrying your baby over your arm on their tummy or side, to take pressure off the back of the head.

For safe naps while you're out, see naps on the go. Car seat naps are fine during the journey; take your baby out when you arrive.

What is torticollis, and how does physiotherapy help?

Torticollis means the neck muscles on one side are tight or shorter, so your baby tilts their head one way and finds it hard to turn the other way. The RCH says this lack of movement can cause a misshapen head, but that it may be avoidable when managed early. The AAP says babies with torticollis will need physiotherapy.

Signs to watch for:

• your baby's head is always tilted to one side
• they always turn to look the same way, even when you're on the other side
• they find it hard to turn their head, or their head tilts one way while their chin points the other, as the AAP describes

The NHS says a baby with torticollis may be referred to a physiotherapist, who will show you gentle exercises to do at home. The AAP says a children's physiotherapist will also check for delayed motor skills from poor head and neck control, and teach stretching and positioning exercises; some babies need weekly therapy. The RCH says one side may seem harder at first, which is normal, and the more you practice the harder way, the easier it gets. If your baby has been diagnosed with torticollis, talk to a children's physiotherapist about the best plan.

Do babies need a helmet for a flat head?

Most don't. Sources differ on how useful helmets are:

The RCH says helmet therapy works best if started between 6 and 8 months and finished before 12 months, while the skull is growing fast. An orthotist makes a lightweight, custom helmet from 3D images of the head, and it reshapes the skull by taking pressure off the flat area so the head grows into the space.

The AAP's helmet therapy FAQs say helmets need to be worn while the skull and brain are actively growing, usually for 23 hours a day for several months, and that three-quarters of brain growth happens by age 2. A helmet is prescribed after a doctor assesses your baby, and fitted by a trained specialist. If you're considering one, ask your doctor or pediatrician whether your baby's flattening is mild, moderate or severe first, because mild flat spots usually improve with position changes alone.

Are positioners, wedges or head-shaping pillows safe?

No. These products are marketed for flat heads, but they make sleep less safe.

• The AAP says head-shaping pillows are not safe because they can create a suffocation risk, and notes the US Food and Drug Administration says there's no evidence they work for flat heads or any other medical purpose.
• Red Nose in Australia says products that restrict the movement of a baby or a baby's head should not be used, and advises against anti-roll devices.
• The Lullaby Trust says there's no need for any equipment or rolled-up blankets to keep a baby in one position, unless a health professional has advised it for a specific medical condition.
• The RCH says not to use pillows in the crib for positioning.

Keep the crib bare apart from a fitted sheet and safe bedding. See sleep products to avoid for the full list.

Is it a flat spot or craniosynostosis?

Rarely, an unusual head shape is caused by craniosynostosis, where the joins between the skull bones close too early. The AAP's craniosynostosis guide estimates it affects about 1 in 2000 US babies. It usually needs surgery, and tummy time and helmets alone don't correct it.

The NHS craniosynostosis page says your baby may have a problem like craniosynostosis if:

• their head is long and narrow, like a rugby ball
• their forehead is pointy or triangular
• one side of their head is flattened or bulging out
• the soft spot on top of their head disappears before they're 1 year old

The AAP adds that a fused join may be felt as a ridge on the head. A classic positional flat spot looks different: viewed from above, the head is shaped like a parallelogram, with the ear and forehead pushed slightly forward on the flat side. The NHS flat head page says some babies are born with a flat head, which may happen if they're born prematurely and is usually nothing to worry about, but rarely it can be a sign of craniosynostosis. Your doctor or pediatrician can examine your baby and refer them to a specialist if needed.

When should I get my baby's head shape checked?

Call 911 now if the soft spot on top of your baby's head looks swollen or bulging, which the NHS urgent-help guide lists as a sign of serious illness. Also call if your baby is struggling to breathe, turns blue, gray or very pale, or is floppy or hard to wake, during tummy time or at any other time.

Talk to your doctor or pediatrician soon (book a visit rather than waiting for the next routine check) if:

• your baby's head looks long and narrow, pointy or triangular at the front, has a ridge, or bulges on one side
• their soft spot seems to have closed early
• their head shape was unusual at birth, or the shape or size of their head is changing in a way that worries you
• their head is always tilted to one side, or they have difficulty turning it, which the NHS says can be torticollis
• they only turn their head one way when lying on their back, which the RCH says is worth getting checked

Mention it at your next check-up, or with your pediatrician, if:

• you notice a flat spot, so you can start position changes early; the NHS says the earlier it's recognised, the easier it is to stop it getting worse
• a flat spot isn't improving after a few weeks of tummy time and position changes, because helmets, if ever needed, are considered from around 5 to 6 months

The RCH suggests your pediatrician, a children's physiotherapist or a doctor as good people to ask. It can help to take a photo of your baby's head from above every few weeks, after a bath, so you can see whether it's changing. See milestones from 0 to 3 months for head control and other skills to watch.