The newborn skull is composed of separate bony plates connected by flexible joints called sutures. This design makes the baby’s head malleable, which is necessary for passage through the birth canal during delivery. The flexibility also accommodates the rapid brain growth that occurs during the first year of life. Minor variations in head shape are common during early infancy and usually do not indicate a serious health concern, often resolving naturally as the baby develops better head control.
Common Reasons for Head Shape Variation
The most frequent cause of a misshapen head in infants is constant external pressure applied to the soft skull bones. This is known as positional flattening, a condition that does not affect brain growth or development. The two main types are positional plagiocephaly and positional brachycephaly, distinguished by the location and pattern of the flatness.
Positional plagiocephaly involves an asymmetrical flattening, typically on one side of the back of the head. The affected side often shows the ear, forehead, and cheek pushed slightly forward compared to the opposite side. Positional brachycephaly, conversely, is a central, symmetrical flattening across the entire back of the head, sometimes making the head appear unusually wide.
These positional issues became increasingly common following the recommendation to place all infants on their backs to sleep, a practice implemented to reduce the risk of Sudden Infant Death Syndrome (SIDS). While the “Back to Sleep” campaign must be strictly followed for safe sleep, extended time spent supine increases pressure on the occipital bone. The issue is compounded by the extensive use of infant carriers, swings, and car seats, which keep the baby’s head in a fixed position for long periods throughout the day.
A common contributing factor to positional flattening is a condition called torticollis, which involves tightness in the neck muscles. If the sternocleidomastoid muscle on one side of the neck is tight or shortened, the baby will develop a strong preference for turning their head to one side while resting. This preference means that the same spot on the skull receives constant pressure, making the development of asymmetrical plagiocephaly more likely. A healthcare provider can often identify and recommend treatment for torticollis, as early intervention is beneficial for correcting both the muscle tightness and the resulting head shape.
Encouraging Natural Head Development
Preventing positional flattening requires relieving pressure on the back of the baby’s head throughout the day. A primary strategy is maximizing “container-free” time, minimizing the amount of time an infant spends lying in devices like car seats, bouncers, or swings while awake. These devices restrict movement and maintain pressure on the same area of the skull.
Supervised “Tummy Time” relieves pressure and strengthens neck and upper-body muscles. It can be safely started from birth, aiming for 15 to 30 minutes total spread throughout the day by around four months of age. Starting with short sessions of one to five minutes several times a day is a manageable way to help the baby become comfortable with the position.
Repositioning techniques during sleep and waking hours also promote a more rounded head shape. Parents must continue to place the baby on their back for sleep but can alternate the direction the baby’s head faces in the crib to encourage turning both ways. Similarly, when feeding, switching the side the baby is held on encourages them to look in different directions.
If conservative positioning and repositioning efforts do not produce noticeable improvement after several months, a specialist may recommend a cranial orthotic, commonly known as a helmet. This custom-molded device works by applying gentle pressure to the prominent areas of the skull while allowing the flattened areas space to round out as the brain grows. Helmet therapy is typically most effective when initiated between four and eight months of age, when the skull bones are still rapidly growing.
When to Consult a Pediatrician Immediately
While most head shape variations are benign, certain signs require prompt medical evaluation to rule out a serious, rare underlying condition. The most significant medical concern is craniosynostosis, where one or more of the sutures between the skull bones fuse prematurely. This is different from positional flattening because it is a problem with bone development, not external pressure.
Premature suture closure prevents the skull from expanding perpendicular to the fused joint, forcing the head into an abnormal shape. This is medically urgent because if multiple sutures fuse, it can restrict the space available for the rapidly growing brain, potentially leading to increased pressure inside the skull.
Parents should seek immediate consultation if they notice concerning signs, including:
- A hard ridge or raised, bony seam along a cranial suture.
- The soft spot (fontanel) disappearing before the expected time or appearing noticeably bulging.
- A head shape that is becoming progressively worse rapidly, despite repositioning efforts.
An asymmetrical appearance where the forehead is bulging on one side, or if the ears appear unevenly positioned, may suggest premature fusion of a suture. Unlike positional flattening, which is generally cosmetic, craniosynostosis can, in certain forms, pose a risk to brain development and may require surgical intervention to allow for proper brain growth. Early diagnosis and treatment are important for a favorable outcome.