27 March, 2026
How Common Is Craniosynostosis?
Craniosynostosis is rare and affects about 1 in every 2,000 to 2,500 babies. It is much less common than flat head syndrome. Large health organizations including the Centers for Disease Control and Prevention report similar numbers.
Most babies with a different head shape do not have craniosynostosis. This does not automatically mean something serious is happening if you notice a flat or uneven area on your baby’s head.
What craniosynostosis means
Craniosynostosis happens when one of the skull’s flexible joints, called a suture, closes too early. Sutures normally stay open during infancy so the brain can grow. If one closes too soon, the skull cannot expand normally in that direction, and the head shape changes in a predictable pattern.
Why it is much less common than flat head syndrome
Flat head syndrome caused by pressure is common, especially between 2 and 6 months when babies spend more time on their backs.
Craniosynostosis is not caused by pressure and does not improve with repositioning. If you notice a flat spot, it is statistically far more likely to be positional flattening than early suture closure.
Different types and how often they happen
The type depends on which suture closes early. The sagittal suture is the most common and accounts for roughly half of cases. Coronal, metopic, and lambdoid types occur less often, and complex forms are rare.
How doctors tell the difference
Doctors examine the baby’s head from multiple angles, feel for ridges along suture lines, and measure head circumference over time. Positional flattening often improves as babies gain mobility.
Craniosynostosis does not improve on its own because the bone has fused.
Can it affect brain growth
When a suture closes too early, skull growth becomes restricted in that area. In some cases, this can affect how the skull expands around the growing brain. This is why doctors evaluate head shape carefully.
Most babies with simple positional flattening do not have brain growth problems.
Signs that need medical attention
You should see a doctor if the head shape looks very unusual, if there is a firm ridge along a suture line, or if head growth seems slower than expected. Doctors compare head measurements over time and may refer to a craniofacial specialist if needed.
If you are unsure whether a head shape difference is common or rare, structured head measurements can provide objective clarity before assuming a serious condition.
What research and hospitals report
You should see a doctor if the head shape looks very unusual, if there is a firm ridge along a suture line, or if head growth seems slower than expected. Doctors compare head measurements over time and may refer to a craniofacial specialist if needed.
If you are unsure whether a head shape difference is common or rare, structured head measurements can provide objective clarity before assuming a serious condition.
What happens if it is diagnosed
If craniosynostosis is confirmed, care is led by a craniofacial team. Treatment often involves surgery to allow the skull to grow normally. Timing depends on the baby’s age and which suture is involved, and outcomes are generally good when managed by experienced specialists.
If you prefer to monitor head growth over time before worrying about rare conditions, consistent measurements can support calm and informed discussions with your healthcare provider.
Common questions parents ask
Is craniosynostosis common?
No, it affects about 1 in 2,000 to 2,500 babies.
Does a flat spot mean craniosynostosis?
No, most flat spots are positional and improve with movement.
Can craniosynostosis fix itself?
No, true suture fusion does not reopen naturally.
Is it life-threatening?
Most cases are treatable when managed by specialists.
Can flat head syndrome turn into craniosynostosis?
No, positional flattening does not cause sutures to close.
Writen by Elly van der Grift
Elly van der Grift is the co-founder of Skully Care and a pediatric physiotherapist with over 30 years of experience. Her mission is to provide top care for babies with skull deformities. With her infectious enthusiasm, she shares simple, effective tips that can make a big difference for your baby. Working with Elly, you'll feel confident and supported in your baby’s journey to better health.