Flat spots on an infant’s head are extremely common and usually represent a benign, cosmetic condition. This phenomenon is medically referred to as positional plagiocephaly or brachycephaly, collectively known as “flat head syndrome.” This change in head shape is a direct result of external pressure on the soft, rapidly growing skull. In the vast majority of cases, this condition is purely external and does not affect the baby’s brain development or neurological function.
Understanding Positional Head Flattening
The two main types of flattening caused by external pressure are positional plagiocephaly and positional brachycephaly. Positional plagiocephaly involves an asymmetrical flattening on one side of the back of the head. This flattening can cause the ear on the affected side to shift forward and may also lead to unevenness in the forehead and face.
Positional brachycephaly is characterized by a central and symmetrical flattening across the entire back of the head. This flattening causes the head to appear unusually wide when viewed from above. Both conditions are categorized as deformational, meaning they result from external forces rather than an internal issue with the skull bones. The distinction between the two types helps determine the best repositioning strategies.
The skull bones of an infant are thin, flexible, and have spaces between them called sutures. This structure allows the head to expand quickly to accommodate the developing brain. Positional flattening occurs because the soft skull is easily molded by consistent external pressure. Since this is a cosmetic issue, it does not impede the brain’s ability to grow.
Why Flat Spots Develop in Infants
The primary reason for the increased incidence of positional flattening is the “Back to Sleep” public health campaign. This campaign recommends placing infants on their backs to sleep to reduce the risk of Sudden Infant Death Syndrome (SIDS). While this position is necessary for safe sleep, it causes babies to spend a significant amount of time with their heads resting on a firm surface. This prolonged contact applies constant pressure to the malleable skull.
Another contributing factor is the time infants spend in restrictive devices like car seats, swings, and bouncers. These devices keep the baby reclined with their head pressed against a surface. Limiting the use of these seats outside of necessary travel can help reduce the pressure that contributes to head flattening.
Flat spots are frequently associated with torticollis, a condition involving tightness or shortening in the neck muscles. Torticollis causes the baby to prefer turning their head to one side, consistently putting pressure on that spot. This muscle tightness can lead to a more severe or persistent flat spot because the infant is physically limited in their ability to turn their head away from the pressure.
Repositioning and Prevention Strategies
Repositioning techniques are the most effective line of defense for preventing and correcting mild to moderate positional flattening. These methods focus on removing pressure from the flat spot and encouraging natural, balanced growth. The goal is to maximize the time the baby spends off the back of their head while awake.
Supervised tummy time is an effective prevention strategy, as it strengthens the neck and upper body muscles needed for head control and keeps the head off the resting surface. Pediatricians recommend beginning tummy time early, with short sessions of three to five minutes, two to three times a day. The goal is to work up to approximately 60 minutes total daily by three months of age. Consistency across the day, such as practicing after every diaper change or nap, is more valuable than trying to achieve one long session.
Parents can practice “counter-positioning” while the baby sleeps by varying the direction the baby faces in the crib. Placing the baby’s head toward the end of the crib encourages them to look away from the flat side, which helps relieve pressure. During awake time, parents should alternate the side they hold or feed the baby on to promote balanced head movement. For babies with a flat spot, all toys and visual stimuli should be placed to encourage turning the head away from the flattened area.
When Medical Intervention is Necessary
For most infants, repositioning and tummy time are enough to correct the head shape, especially if started before four months of age. When these conservative measures do not produce sufficient improvement, or the flattening is severe, medical intervention may be considered. The most common treatment for moderate to severe positional flattening is a cranial orthotic, often called a helmet.
These custom-made helmets work by applying gentle pressure to the prominent areas of the skull while allowing flat areas room to grow and round out. Treatment is most effective when started between four and eight months, when the skull is still growing rapidly. The helmet is worn for up to 23 hours a day for three to six months, with frequent adjustments made as the head shape changes.
A more serious, though rare, cause of an abnormal head shape is craniosynostosis. This condition occurs when the skull’s growth plates, or sutures, prematurely fuse. Unlike positional flattening, craniosynostosis can restrict brain growth and development, making a prompt diagnosis by a specialist essential. Signs may include a bony ridge over the prematurely closed suture or a lack of improvement despite aggressive repositioning efforts. This condition requires surgical correction to allow the brain to grow normally.