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Why plagiocephaly (flattening of the head) happens and what to do about it

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This blog post covers plagiocephaly, or flattening of the head on babies. We’ll discuss why it happens, prevention tips and when helmet therapy is needed.

Check out this PedsDocTalk YouTube video on plagiocephaly for additional resources!

Let’s discuss some terms and why flattening happens

Plagiocephaly is an asymmetric flattening on the head of a baby. People sometimes refer to this as flat head syndrome or deformational plagiocephaly. This is different from something called craniosynostosis. Craniosynostosis is when a baby’s skull bones fuse together before they are supposed to. In deformational plagiocephaly, there is no fusion of the skull bones. That is why your clinician should be looking at the child’s head shape at every visit from birth. If you are concerned at any point of your baby having an unusual head shape, early evaluation is important.

Craniosynostosis is a condition that needs referral to a neurosurgeon. It is rare but it is different from plagiocephaly and your clinician would make the differentiation based on an exam. In craniosynostosis, there is an early fusion of a suture that causes the head shape to change. This typically causes changes not only in the back/side but when looking at the front of the face as well. In positional plagiocephaly, sutures are opening, but friction has caused the soft and malleable skull of a newborn/infant to become flat in some spots. 

Why are we seeing more babies with flat spots on their heads?

The first 6 months of a baby’s life is the time when the skull is most malleable, hence why we see this commonly during this time frame. Since 1992 when the AAP instituted the back to sleep campaign for safe sleep, infants have been spending more time on their backs. Babies commonly are sleeping in reclined positioners, bouncy seats, swings, car seats, etc. which adds friction to a soft/malleable skull, leading to the flat spots we see. If a baby has a preference to one side, we can see softening on one side, or it can be bilateral and make the back of head look flat. In 2017, 3.8 million babies were born in the US and about 720,000 had plagiocephaly. 

What is torticollis and why does it matter?

Torticollis is a tightening of a muscle in the neck called the Sternocleidomastoid. This tightening can be congenital (from birth) or acquired (developed). Congenital torticollis happens due to intrauterine positioning or during delivery. If moderate to severe, it can lead to a preference for one side, leading to flattening. It is my recommendation that if your baby has torticollis, you should visit a PT to learn stretching exercises early to prevent moderate to severe flattening. This early evaluation can help teach you the skills to stretch out that neck muscle to reduce risk of flattening. 

How can you prevent flat spots?

  • Evaluating for torticollis—I highly suggest PT for assistance in stretching exercises/frequency of visits. It may not be often but it is useful.  
  • Limiting time in “baby containers” when possible like bouncers/chairs/ swings.
  • Alternating directions you lay the baby down in their crib/bassinet and putting baby on alternate sides to sleep for side preference. One day, place your baby with his head toward the head of the crib. The next day, place your baby with his head toward the foot of the crib.
  • Tummy time. During play, tummy time and mirrors entice them to look to other sides. Many times it’s side preference, and mirrors and toys can encourage play on the other side OR YOU!
    • Favorite ways:
      • Baby lays with face to parents chest
      • Baby lays over parent lap
      • Chest down, hold over arm
      • Baby lays on floor with roll under chest or pillow
      • Straight on floor 
      • Exciting items for them to look at during floor time
  • Side-lying on the opposite side of any flattening (this is useful if you are seeing flattening. For example, if flattening is on the back right of the head, lay them on their side on the left during play time. They can play with a toy midline to keep their concentration.
  • Avoid head shaping pillows. These are not safe sleep items!! 

What does plagiocephaly look like?

Plagiocephaly can look like a normal head shape, unilateral plagiocephaly, or in some plagipcerhaly cases you can see the forehead being pushed forward.

Check out this PedsDocTalk YouTube Video for visual examples of flat spots.

Brachycephalic plagiocephaly

From the top of the head in moderate and severe cases, you can see the ear being pushed forward and the forehead even coming forward.

What should be evaluated at clinician visits 

Your doctor should be checking the motion of the neck, head shape, and looking from above. Before one month, if there is any concern, it needs to be evaluated as it may not be positional but more craniosynostosis. For torticollis, I recommend seeing a PT. If your child is between 1-3 months and it is mild, do the things I mentioned for prevention. For a child presenting moderate to severe at two months, really dive into the importance of tummy time, and all things I mentioned. If at four months, it is still moderate to severe, I recommend helmet therapy as I do believe the best time to do helmet therapy is between 4-5 months when the skull is still malleable (before ossification).

Is this just cosmetic?

Largely, flattening and intervening is cosmetic. However, there was a small study that was released in Contemporary Pediatrics looking at 336 9-year-olds who had positional plagiocephaly in infancy. Cognitive and academic scores were average, however those with moderate to severe plagiocephaly scored lower than those with mild cases. Truly, we don’t know if this is multifactorial or other things such as the environment.

Does helmeting really work?

Helmeting DOES work, especially when done before 12 months when the skull is more malleable (I believe 4-7 months is the best time to do it if prevention didn’t avoid it). I only recommend this for moderate to severe plagiocephaly. For mild, please follow the tips I mentioned. There are some important downsides to helmeting, including time, expenses, irritation, and the stigma.

My goal here is prevention and monitoring with hopefully removing stigma IF your child needs a helmet. Prevention and education are key in my opinion. However, so is not shaming parents! I think a lot of developmental accounts do. Know the way to prevent this, and understand what your options are for management for you and your baby. 

If you are an expecting mom or have a baby who is under 6 months of age, join The New Mom’s Survival Guide—an online digital e-course and community created by me to educate and empower moms through their first year of motherhood! 

P.S. – Shop my favorite floor time toys on Amazon!

Dr. Mona Admin

Hi there!

I’m a Board Certified Pediatrician, IBCLC, and a mom of two.

I know the ups and downs of becoming a mom and raising kids.

I help moms ditch the worry and second-guessing so you can find more joy in motherhood.


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