Parental concern over a newborn’s head shape is a frequent source of anxiety. The infant skull is remarkably pliable, designed to accommodate passage through the birth canal and the rapid brain growth that follows. These natural processes mean a baby’s head shape is highly variable in the first months of life. While many changes are temporary and resolve spontaneously, some require intervention or signal a more serious underlying condition. Knowing the difference between common flattening and a true medical concern provides necessary guidance and peace of mind.
Common and Expected Head Shape Changes
The initial changes in a newborn’s head shape are often a direct result of the birth process. During a vaginal delivery, the soft, unfused skull plates compress and overlap, a process called molding, which allows the head to pass through the narrow birth canal. This can leave the baby’s head elongated or slightly cone-shaped at first, but this temporary shaping typically corrects itself within a few days to a week after birth.
Other transient swellings occur due to the physical stresses of delivery. A caput succedaneum is a soft, puffy swelling of the scalp tissue that often crosses the suture lines and generally disappears within a few days. A cephalohematoma involves a collection of blood beneath the outer membrane of a skull bone; it is firmer, does not cross suture lines, and may take several weeks or months to fully absorb. Neither condition typically requires treatment, as they resolve when the fluids are naturally reabsorbed by the body.
Understanding Positional Plagiocephaly
The most frequent cause of an uneven or flattened head shape developing after birth is positional flattening, often referred to as deformational plagiocephaly or brachycephaly. Positional plagiocephaly is characterized by an oblique, unilateral flattening on one side of the back of the head, which can cause the ear and forehead on the same side to shift forward. Positional brachycephaly is a central, symmetrical flattening across the entire back of the head, giving it a wider appearance.
These positional conditions are not structural defects but are caused by sustained external pressure on the soft, rapidly growing skull. The widespread adoption of the “Back to Sleep” campaign, which recommends placing infants on their backs to reduce the risk of sudden infant death syndrome (SIDS), has led to an increase in these positional changes. Prolonged time spent in a fixed position, such as in car seats, swings, or bouncers, also contributes to the flattening. This condition is purely cosmetic and does not affect brain development or growth.
Interventions focus primarily on consistently relieving pressure from the flattened area. Parents should incorporate frequent, supervised “Tummy Time” sessions while the baby is awake to strengthen neck muscles and keep pressure off the back of the head. Repositioning techniques involve encouraging the baby to turn their head away from the flat spot during sleep and awake periods, for example, by changing the direction they face in the crib. These non-medical strategies are the first line of defense and are often sufficient to correct mild to moderate flattening, especially when started early in infancy.
Red Flags and Serious Concerns
While most head shape variations are positional, parents should be aware of signs that indicate a more serious underlying condition. The primary concern is craniosynostosis, a relatively rare condition where one or more of the fibrous sutures between the skull bones prematurely fuse. This early fusion prevents the skull from expanding normally in that area, forcing the head to grow unevenly in other directions, resulting in an atypical head shape.
Unlike positional flattening, craniosynostosis is a structural problem and can restrict brain growth, potentially leading to increased pressure inside the skull, developmental issues, or vision problems if untreated. Visual cues include a palpable, raised ridge of bone felt along the prematurely fused suture line. The resulting head shape is often severely abnormal and does not respond to repositioning efforts.
A failure of the head circumference to grow along the expected curve on a pediatrician’s chart is a significant red flag. Other signs of elevated intracranial pressure include a bulging soft spot (fontanel), inconsolable fussiness, or poor feeding.
Medical Assessment and Treatment Options
If repositioning efforts fail to improve a noticeable head shape variation, or if a parent observes any red flags, a medical assessment is necessary. The initial step is a thorough physical examination by a pediatrician, who will measure the head circumference and feel the skull for any unusual ridges or restricted movement. This clinical examination helps differentiate between a benign positional issue and a structural problem like craniosynostosis.
For a definitive diagnosis, advanced imaging tests such as X-rays or a Computed Tomography (CT) scan are used to visualize the skull sutures. The treatment pathway depends entirely on the diagnosis.
For moderate to severe positional plagiocephaly that has not responded to repositioning, a custom-fitted cranial orthosis, often called a helmet, may be prescribed. This device works by providing gentle, consistent pressure to redirect the rapid growth of the infant’s skull over several months. Treatment for craniosynostosis is almost always surgical, which involves opening the fused suture to allow the brain adequate space to grow and to reshape the skull. In some cases, a helmet may be used after this surgery to further refine the skull shape.