Flat Head (Positional Plagiocephaly)
The short answer
Flat spots on a baby's head are very common and almost always caused by positioning, not a structural problem. Most positional flat spots improve significantly with simple repositioning strategies and supervised tummy time.
By Age
What to expect by age
Newborn heads are soft and mouldable by design. A slight flattening from sleeping position is extremely common at this age. Alternating which direction your baby faces during sleep can help prevent a flat spot from developing.
This is when positional flattening is often most noticeable, because babies spend a lot of time on their backs (which is the safest sleep position). Increasing supervised tummy time and varying your baby's head position during awake periods is the main approach.
As babies gain head control and start rolling, many flat spots begin to improve on their own. If a flat spot is moderate to severe, this is the window when a helmet (cranial orthosis) is most effective, typically starting around 4-6 months.
Most mild to moderate flat spots have improved considerably by now as your baby spends more time upright. Helmet therapy is less effective after about 12 months because skull growth slows. Hair growth also helps conceal any remaining asymmetry.
The skull continues to remodel gradually throughout early childhood. Many parents who were worried at 3-4 months find the shape has rounded out significantly by this age. Residual mild asymmetry is common in the general population and rarely causes any issues.
What Should You Do?
When to take action
- A mild flat spot on one side of the head, especially if your baby has a preferred sleeping position
- The flat area is improving with repositioning and increased tummy time
- Your baby's ears appear roughly symmetrical and the forehead is not noticeably pushed forward on one side
- Your baby moves their head freely in both directions when awake
- Your baby was born with some moulding from the birth canal that is gradually resolving
- The flat spot seems to be getting worse despite repositioning efforts
- Your baby strongly prefers turning their head to one side and resists turning the other way, which may suggest torticollis
- You notice the ear on the flat side appears pushed forward, or the forehead is more prominent on one side
- The flat spot is still significant at 4 months and you want to discuss whether a helmet evaluation makes sense
- You notice a ridge or raised line along the top or side of your baby's skull, which could indicate craniosynostosis rather than positional flattening
- The head shape appears to be worsening rapidly or is accompanied by other developmental concerns
Sources
Related Resources
Related Physical Concerns
My Baby Seems to Use One Side More Than the Other
Babies should use both sides of their body fairly equally during the first 18 months of life. While slight preferences can be normal, a consistent pattern of favoring one side - using one arm much more than the other, crawling with one leg dragging, or turning the head predominantly one way - should always be discussed with your pediatrician. Early identification of asymmetry leads to the best outcomes.
My Baby Curls Their Toes
Toe curling is very common in babies and is usually caused by the plantar grasp reflex, which is a normal newborn reflex that causes toes to curl when the sole of the foot is touched. This reflex typically fades by 9-12 months. Occasional toe curling during standing or walking is also normal as babies figure out their balance. Persistent, tight toe curling past 12 months may warrant a mention to your pediatrician.
My Baby Favors One Leg
Babies should use both legs roughly equally when kicking, crawling, and eventually walking. If your baby consistently favors one leg or seems to avoid using the other, it is worth having your pediatrician take a look. The cause is often something simple and treatable, like a minor hip or muscle issue, but early evaluation helps ensure the best outcome.
My Baby Gets Hiccups a Lot
Hiccups are extremely common in babies, especially newborns, and are almost always completely harmless. They happen because your baby's diaphragm is still developing and gets a little jumpy when their tiny stomach fills up or air gets swallowed. Most babies outgrow frequent hiccupping by 6-9 months.
My Baby Has Jerky Movements
Newborns and young babies often have jerky, uncoordinated movements because their nervous systems are still developing. What looks like random flailing is actually your baby learning how their body works. These movements typically become smoother and more controlled by 3-4 months as motor skills mature.
Baby Not Bearing Weight on Arms
Bearing weight on the arms is a gradual skill that develops during the first 6 months. Babies first prop up on their forearms around 2 to 4 months, then progress to pushing up on extended arms by 5 to 6 months. Regular tummy time is the best way to build this strength, even if your baby protests at first.