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What Is Flat Head Syndrome?

Flat head syndrome usually happens when a baby sleeps with the head turned to the same side during first months of life. This causes a flat spot, either on one side or the back of the head.

Flat head syndrome is also called positional plagiocephaly (pu-ZI-shu-nul play-jee-oh-SEF-uh-lee).

What Causes Flat Head Syndrome?

The most common cause of a flattened head is a baby's sleep position. Infants are on their backs for many hours every day, so the head sometimes flattens in one spot. This happens not only while they sleep, but also from being in infant car seats, carriers, strollers, swings, and bouncy seats.

Premature babies are more likely to have a flattened head. Their skulls are softer than those of full-term babies. They also spend a lot of time on their backs without being moved or picked up because of their medical needs, such as a stay in the neonatal intensive care unit (NICU).

Flat head syndrome can even start before birth if there's pressure on the baby's skull from the mother's pelvis or a twin. In fact, many babies from multiple births are born with heads that have some flat spots.

Flat head syndrome is often caused by tight neck muscles that make it hard for babies to turn their heads. This neck condition is called torticollis. Because it's hard to turn their head, babies tend to keep their heads in the same position when lying down. This can cause flattening. Then, once the head has a flat spot, the torticollis (tor-ti-KOLL-iss) can get worse.

It takes a lot of energy for babies to turn their heads. So those with severe flattening on one side tend to stay on that side, and their necks become stiff from lack of use.

What Are the Signs & Symptoms of Flat Head Syndrome?

Flattened head syndrome usually is easy for parents to notice:

  • The back of the baby's head is flatter on one side.
  • The baby usually has less hair on that part of the head.
  • When looking down at the baby's head, the ear on the flattened side may look pushed forward.

In severe cases, the forehead might bulge on the side opposite from the flattening, and may look uneven. If torticollis is the cause, the neck, jaw, and face also might be uneven.

How Is Flat Head Syndrome Diagnosed?

Doctors often can diagnose flat head syndrome by looking at the baby's head. To check for torticollis, the doctor may watch how a baby moves the head and neck. Medical tests usually are not needed.

How Is Flat Head Syndrome Treated?

Caregivers should always place babies on their back to sleep to help prevent sudden infant death syndrome (SIDS), even with possibility of flat head syndrome. Avoiding swings, car seats, bouncy chairs, and other devices is safest for sleep and also helps to make sure that babies can move their head freely.

So what can parents do when flat head syndrome is due to a sleeping or lying position? Simple practices like changing a baby's sleep position, holding your baby, and providing lots of "tummy time" can help it go away. Try these tips:

  • Practice tummy time. Provide plenty of supervised time for your baby to lie on the stomach while awake during the day. Tummy time:
    • helps normal shaping of the back the head
    • encourages a baby's learning and discovery of the world
    • helps babies strengthen their neck muscles and learn to push up on their arms. This helps develop the muscles needed for crawling and sitting up.
  • Vary positions in the crib. Consider how you lay your baby down in the crib. Most right-handed parents carry infants cradled in their left arms and lay them down with the heads to their left. In this position, the infant must turn to the right to look out into the room. Position your baby in the crib to encourage active turning of the head to the side that's not flattened. Don't use wedge pillows or other devices to keep your baby in one position.
  • Limit time in "containers." Limit the time your child spends lying on the back or with the head resting against a flat surface (such as in car seats, strollers, swings, and bouncy seats). For instance, if your baby has fallen asleep in a car seat, take your baby out of the seat when you get home rather than leaving your little one snoozing in the seat.

Most babies with flat head syndrome also have some degree of torticollis. So stretches at home and physical therapy usually are part of treatment. A physical therapist can teach you exercises to do with your baby involving stretching. Most moves involve stretching the neck to the side opposite the tilt. In time, the neck muscles will get longer and the neck will straighten itself out. The exercises are simple, but must be done correctly.

A doctor may prescribe a helmet for flat head syndrome. The helmet is designed to fit a baby loosely where the head is flat and tightly where it is round. In the helmet, the head can't grow where it is already round. So it grows where it's flatter.

Helmets make the head rounder quicker than time and normal growth. On average, though, babies who get helmets and those who don't have the same results after a couple years. Talk to your doctor about whether a helmet could help your baby.

What Else Should I Know?

Flat head syndrome improves with time and natural growth. As babies grow, they begin to change position themselves during sleep, so their heads aren't in the same position.

When babies can sit on their own, a flat spot usually won't get any worse. Then, over months and years, as the skull grows, the flattening will improve, even in severe cases. As hair grows in over the first few years, the flat spot often becomes less noticeable as well.

Flat head syndrome doesn't affect a baby's brain growth. But having a stiff neck can slow early development. Physical therapy for torticollis should include a check of the baby's progress and extra exercises to treat any delays.

Date reviewed: May 2023