Flat Head (Positional Plagiocephaly)
Medically reviewed by Dr. Sarah Chen, MD, FAAP · Board-Certified Pediatrician
Content reviewed against published AAP, CDC, AAP guidelines
Last reviewed:
Your baby's physical development is unique, and concerns about flat head (positional plagiocephaly), here is what you need to know.
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.
Key takeaways
- 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.
- Usually normal when: A mild flat spot on one side of the head, especially if your baby has a preferred sleeping position
- Call your doctor if: 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
- Varies by age — see the age-by-age breakdown below
“Supervised tummy time is recommended daily from the time the baby comes home from the hospital to help prevent flat head syndrome and to strengthen neck and shoulder muscles.”
This is one of the most common questions parents ask. Searching for answers means you care.
What Parents Should Know
According to AAP, CDC guidelines, 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. At 0-2 months, 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. It is generally considered normal when a mild flat spot on one side of the head, especially if your baby has a preferred sleeping position. However, you should contact your pediatrician promptly if 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.
Normal vs. Concerning
By Age
What to expect by age
0-2 months
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.
2-4 months
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.
4-8 months
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.
8-12 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.
12 months+
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 to Tell Your Pediatrician
- Describe when you first noticed flat head (positional plagiocephaly) and how it has changed over time.
- Note your baby's current age and which age-specific patterns you are seeing.
- Mention if the flat spot seems to be getting worse despite repositioning efforts.
- Mention if your baby strongly prefers turning their head to one side and resists turning the other way, which may suggest torticollis.
- Bring a list of any questions or observations you want to discuss at the appointment.
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
What You Can Do at Home
- Keep track of when you notice flat head (positional plagiocephaly) — noting the time of day, duration, and any triggers can help your pediatrician.
- Remember that a mild flat spot on one side of the head, especially if your baby has a preferred sleeping position — this is generally within the range of normal.
- At 0-2 months, focus on observation rather than intervention unless your pediatrician advises otherwise.
- Provide plenty of supervised floor time and tummy time to support your baby's physical development.
- While monitoring at home, seek immediate care if 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.
Related Resources
Milestone Checklists by Age
Track your baby's developmental milestones from birth to 5 years with age-specific checklists.
Month-by-Month Development
Detailed monthly development guides from birth through 24 months.
When to Call the Doctor
General guide on when to call the pediatrician, visit urgent care, or go to the ER.
Frequently asked questions
Is flat head (positional plagiocephaly) normal?
When should I call the doctor about flat head (positional plagiocephaly)?
When is flat head (positional plagiocephaly) normal?
What causes flat head (positional plagiocephaly)?
What should I mention to my pediatrician about flat head (positional plagiocephaly)?
Is flat head (positional plagiocephaly) normal at 0-2 months?
Is flat head (positional plagiocephaly) normal at 2-4 months?
Should I go to the ER for flat head (positional plagiocephaly)?
Does flat head (positional plagiocephaly) go away on its own?
References
- [1]American Academy of Pediatrics. Prevention and Management of Positional Skull Deformities in Infants. Pediatrics, 2011. AAP
- [2]Centers for Disease Control and Prevention. Facts about Craniosynostosis. CDC
- [3]HealthyChildren.org. Flat Head Syndrome (Positional Plagiocephaly) & Torticollis: Parent FAQs. AAP
Doctor Visit Checklist
Bring this checklist to your next pediatrician visit to discuss Flat Head (Positional Plagiocephaly).
Things to mention
- Describe when you first noticed flat head (positional plagiocephaly) and how it has changed over time.
- Note your baby's current age and which age-specific patterns you are seeing.
- Mention if the flat spot seems to be getting worse despite repositioning efforts.
- Mention if your baby strongly prefers turning their head to one side and resists turning the other way, which may suggest torticollis.
- Bring a list of any questions or observations you want to discuss at the appointment.
Observations to share
- 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
Urgent signs to report immediately
- 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
My notes
From ismybabyalright.com — free, evidence-based baby health guides
All content follows our editorial policy and is reviewed against published clinical guidelines.
2,705 evidence-based guides6 authoritative medical sources5 medical advisory board members
Related Resources
Bottom line
Most cases of flat head (positional plagiocephaly) are normal. Talk to your pediatrician if 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.
Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.
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