Noticing an irregular shape to your baby’s head can be a source of significant concern, but head shape variations are common in infancy and are often manageable with early attention. A baby’s skull bones are soft and pliable, necessary for passage through the birth canal and rapid brain growth during the first year of life. When external pressure is repeatedly applied to one area of the soft skull, a flat spot can develop, leading to what is often called “flat head syndrome.” This condition is medically known as deformational or positional cranial asymmetry. For more severe cases, a cranial remolding helmet may be recommended to gently guide the skull’s growth.
Understanding Cranial Asymmetry: Plagiocephaly and Brachycephaly
The two main forms of positional head shape changes that might lead to a helmet recommendation are plagiocephaly and brachycephaly. Plagiocephaly is characterized by an asymmetrical deformation where flattening occurs on one side of the back of the head, causing the head to take on a parallelogram shape when viewed from above. Brachycephaly is a symmetrical flattening spanning the entire back of the head, resulting in a head that is disproportionately wider than it is long and foreshortened. These deformational conditions, resulting from external forces, are distinct from craniosynostosis, a rare condition where the skull’s growth plates fuse prematurely, which typically requires surgical intervention.
Visual Signs Parents Can Identify at Home
Signs of Plagiocephaly
Parents can begin assessing their baby’s head shape by positioning themselves to get a “bird’s eye view,” looking down from the top of the baby’s head while they are lying down. For plagiocephaly, look for a noticeable diagonal flat spot on the back of the skull. This asymmetry often extends beyond the flat spot, causing the ear on the flattened side to appear pushed forward. It can also lead to a slight bulge or prominence on the forehead on the opposite side of the head.
Signs of Brachycephaly
To check for brachycephaly, examine the back and side profile of the head. A key sign is a flat, steep slope across the entire rear of the head, rather than a gentle curve. This bilateral flattening forces the skull to widen sideways, creating a head that appears much broader than normal. In advanced cases, the head may also seem unusually tall due to the lack of front-to-back growth. The presence of a bald spot on the flattened area can often be another visual cue indicating where pressure is consistently placed.
Positional Causes and Early Intervention Strategies
These head shape changes are largely a side effect of the “Back to Sleep” campaign, which recommends placing babies on their backs to sleep and significantly reduces the risk of Sudden Infant Death Syndrome (SIDS). Since infants spend many hours sleeping and resting on their backs, the constant pressure can mold the soft skull. A common contributing factor is congenital muscular torticollis, a condition involving tightness in the neck muscles that causes a baby to favor turning their head to one side, ensuring the same part of the head receives pressure over time.
The primary strategy to address positional flattening is repositioning, which involves actively reducing the time spent resting on the flat spot while the baby is awake. Supervised Tummy Time is paramount, as it relieves pressure on the back of the head and helps strengthen neck and trunk muscles. When carrying or feeding the baby, parents should alternate the side they hold them on to encourage turning the head in different directions. Limiting the time a baby spends in “containers” like car seats, swings, or bouncers is also beneficial, as these devices keep the head in a fixed, supine position.
Medical Evaluation and the Helmet Recommendation Process
If parents notice a persistent flat spot or a strong head-turning preference, they should consult their pediatrician, who routinely screens for head shape issues during well-child checkups. The pediatrician may refer the baby to a specialist, such as a pediatric neurosurgeon, physical therapist, or orthotist, who can perform a more detailed assessment. Specialists use advanced tools, like 3D cranial scanners or anthropometric calipers, to take precise measurements of the skull’s dimensions.
For plagiocephaly, the Cranial Vault Asymmetry Index (CVAI) is calculated to quantify the difference between two diagonal measurements of the head. For brachycephaly, the Cephalic Index (CI), a ratio of head width to length, is used to determine severity. A helmet, known as a cranial remolding orthosis, is typically recommended for moderate to severe cases, generally when conservative repositioning efforts have not produced sufficient correction. The ideal treatment window usually begins around four to six months of age because the skull is still growing rapidly, and the helmet works by applying gentle pressure to the prominent areas while allowing growth in the flattened spots.