Plagiocephaly is the term given to children who have developed the most common form of flat head syndrome. Although there are many causes (such as premature fusion of the skull plates), the most common form of flat head syndrome is caused by position.

Because babies are born with skull segments that have not yet fully joined together, sustained time in a single position can lead to flattening of the side of the skull. The “back to sleep” movement has been critical to decrease the risk of sleep-related death in infants, but we have seen more positional flattening of the back of the skull (brachycephaly) as a result. Some babies also develop flattening of the skull on one side (parietal plagiocephaly). Oftentimes plagiocephaly is associated with torticollis (tightening of the neck muscles).

Is it serious?

In most cases, this condition is mild, especially if caught early. Your pediatrician will assess for it at every well child check. Simple changes in environment, repositioning, and work with an experienced physical therapist can make a tremendous difference to help it improve fairly quickly. In severe cases, an orthotic helmet can be used (the data shows that in mild cases, helmets do not make any difference). In more severe cases of torticollis or craniosynostosis, infants may need surgery, but this is rare.

Sometimes the head position and asymmetrically tight muscles can also cause a domino effect of other problems, such as limited movement of the muscles on one side of the body, and some delay in milestones.

Preventing flat head syndrome

There is an entire market devoted to products that claim to prevent flat head syndrome. Many are sleep or head positioners, which are not safe (and do not work).

From a practical standpoint, the best things a parent can do are:

• Limit time spent in containers (anything that a baby is placed in that restricts their movement — for example, stroller, carrier, high chair, bouncer, etc). Try to do no more than 10-15 minutes at a time and offset it by allowing at least the same amount of time for unrestricted movement.
• Work on building core strength via tummy time: do this when baby is awake, alert and supervised. Try to work up to 30 minutes in total over a 24h period in bursts of 3-5 minutes.
• If your baby tends to rest their head to one side while sleeping, you can either manually and gently rotate the head to the other side while asleep or change what is on the other side of the crib so it is more enticing to look at. I often see that babies orient their heads towards the side of the bassinet where their parents are located, so rotating the direction the baby sleeps by 180 degrees can achieve the same goal.

Although it may be tempting to place your infant down to sleep in other positions, remember that your biggest priority is to keep your infant safe: this means they should be placed on their back, on a flat sleep surface, without anything in the sleep space with them.

What to do if you’re concerned about plagiocephaly:

I recommend discussing this with your pediatrician as soon as you notice any asymmetry. The duration of physical therapy is shorter if a referral is made at an earlier age.