What Is Plagiocephaly? Signs, Causes & Treatment Options
If you've noticed that your baby's head looks a little flat on one side or in the back, you're not alone — and you're right to pay attention. Flat head syndrome is one of the most common concerns parents bring to their pediatrician in the first few months of life. The good news: it's very treatable, especially when caught early, and it has nothing to do with your baby's intelligence or brain development.
Studies show positional plagiocephaly affects approximately 20% of babies — and some research puts that number even higher, with prevalence rates up to 46–48% observed in infants between 7 and 12 weeks of age. You are far from alone if your pediatrician has flagged your baby's head shape.
What Is Plagiocephaly?
Plagiocephaly — sometimes called flat head syndrome — is a condition in which a baby's skull develops an asymmetrical or flattened shape. The word itself comes from the Greek words plagios (oblique or slanted) and kephalē (head). The most common form is positional plagiocephaly, also known as deformational plagiocephaly, which occurs when external pressure causes the soft skull bones to flatten or shift over time.
It's important to understand what plagiocephaly is not: it is not craniosynostosis, a separate and more serious condition in which the skull bones fuse prematurely. Positional plagiocephaly is purely a shaping issue caused by how pressure is distributed on the skull — the bones themselves are completely normal, the sutures (the joints between skull plates) are open and healthy, and there is no compression or harm to the brain whatsoever.
A baby's skull is intentionally soft and pliable at birth to allow for a safe journey through the birth canal and to accommodate rapid brain growth in the first year of life. That same softness, however, means the skull can be reshaped by sustained pressure — whether from a preferred resting position, a tight neck muscle, or other factors. When that reshaping goes unchecked, the result is a noticeably flat spot on the back or side of the head, sometimes accompanied by facial asymmetry.
Common Causes of Baby Flat Head
Positional plagiocephaly rarely has a single cause. More often, it results from a combination of factors that place repeated or prolonged pressure on the same part of your baby's skull. Understanding the causes can help you work with your care team to address them effectively.
Common Risk Factors
- Back sleeping (Safe to Sleep guidelines) — The American Academy of Pediatrics recommends placing babies on their backs to reduce the risk of SIDS. While this recommendation has saved thousands of lives, it has also led to a significant rise in positional plagiocephaly, as babies spend many hours in the same position.
- Torticollis (tight neck muscle) — Congenital muscular torticollis is a tightening of the sternocleidomastoid muscle on one side of the neck, which causes the baby to tilt or rotate the head in one preferred direction. This creates a pattern of pressure on one area of the skull and is one of the leading contributors to plagiocephaly.
- Premature birth — Premature babies have softer, more malleable skulls than full-term infants, and they often spend extended time in the NICU lying in one position. This makes them significantly more susceptible to skull deformation.
- Multiple gestation (twins, triplets) — Babies sharing a womb have less room to move, which can lead to in-utero positional constraints and skull molding even before birth.
- In-utero positioning — Extended positioning against the pelvis or uterine wall during the final weeks of pregnancy can put sustained pressure on the skull before your baby even arrives.
- Extended time in infant gear — Car seats, bouncers, swings, and rockers can all contribute to prolonged pressure on the same area of the skull when babies spend significant time reclining in them.
Signs and Symptoms to Watch For
Most parents notice something looks different about their baby's head shape somewhere between 2 and 4 months of age. You might notice it most clearly when looking at your baby from above, or when comparing photos from different angles. Here are the most common signs of positional plagiocephaly:
Parents often have the sharpest eye for these early changes. If something feels off — trust that instinct and mention it to your pediatrician. Early identification, ideally before 6 months, opens up the most treatment options.
When Should You Be Concerned?
Not every flat spot requires active treatment. Mild cases of positional plagiocephaly — where the asymmetry is subtle and caught very early — can sometimes resolve on their own with consistent repositioning and increased tummy time during the first few months. If your baby is young (under 3–4 months) and the flattening is minor, your pediatrician may start with a watchful waiting approach combined with repositioning guidance.
Moderate or severe plagiocephaly — or cases that do not respond to repositioning within 4–8 weeks — warrant a professional evaluation by a certified cranial orthotist. A specialist can take precise measurements of your baby's head shape and provide an objective assessment of severity, helping you and your pediatrician make an informed decision about next steps. There is no downside to seeking an evaluation; early information always gives you more options, not fewer.
Plagiocephaly Treatment Options
Treatment depends on the severity of the flattening, your baby's age, and whether an underlying condition like torticollis is contributing. Most treatment plans incorporate one or more of the following approaches:
Repositioning techniques. For mild cases or as an early intervention, repositioning focuses on reducing pressure on the flat spot. This includes alternating which end of the crib your baby's head is placed at (encouraging them to turn their head in different directions to look at you), varying the arm you hold your baby on, and reducing time in car seats, bouncers, and rockers when your baby does not need to be secured in them. Increased supervised tummy time is essential — it not only relieves pressure on the back of the skull but also builds the neck, shoulder, and core strength your baby needs for developmental milestones.
Physical therapy for torticollis. If a tight neck muscle is preventing your baby from moving their head freely, a pediatric physical therapist can teach you gentle stretching exercises to perform at home and provide hands-on treatment to improve range of motion. Addressing torticollis directly often helps plagiocephaly improve more quickly, because once a baby can rotate their head fully, they naturally begin distributing pressure more evenly.
Cranial helmet therapy. For moderate to severe plagiocephaly, or cases that have not responded sufficiently to repositioning, a custom-fitted cranial remolding orthosis — commonly called a cranial helmet or band — is the most effective treatment option. The helmet works by creating a space on the flat side of the head, allowing the naturally growing skull to fill in that space while gently redirecting growth away from the fuller side. At Cranial Center, we fit both the STARband and Talee cranial remolding systems — two of the most clinically proven options available. Each helmet is custom-fabricated based on a precise 3D scan of your baby's head and is worn 23 hours a day, typically for 2 to 4 months depending on severity and age at the start of treatment.
Why Choose Cranial Center in New Jersey?
Cranial Center has been helping New Jersey families navigate plagiocephaly for years, and we were the first practice in New Jersey to offer the STARband digital scanning system — a fast, radiation-free, and completely comfortable scan that captures a precise 3D image of your baby's head in seconds. Our lead clinician is certified by the American Board for Certification in Orthotics, Prosthetics & Pedorthics (ABC), the gold standard for cranial orthotics practitioners. With three convenient locations in Hackensack, Hazlet, and Morristown, we're accessible to families across northern and central New Jersey. We offer complimentary consultations — no cost, no commitment, and no referral needed in most cases — because we believe every parent deserves clear, honest answers about their baby's head shape before making any decisions.
Schedule a Complimentary Consultation
Our certified orthotist will evaluate your baby's head shape, answer every question you have, and walk you through your options — with zero pressure. Most families leave feeling reassured and informed, regardless of whether treatment is needed.
800 685 9116 Book Your Free EvaluationFrequently Asked Questions
Positional plagiocephaly is not dangerous to your baby's brain or neurological development. The brain has its own internal pressure regulation, and a flattened skull caused by external positioning does not compress or harm brain tissue. However, untreated moderate-to-severe plagiocephaly can lead to persistent facial and head asymmetry, which can occasionally affect how glasses frames or helmets fit later in life. More significantly, if the flattening is caused by untreated torticollis, that neck tightness can affect motor development if not addressed. For these reasons, it's worth getting an evaluation rather than assuming the condition will resolve on its own.
The ideal window for cranial helmet therapy is between 4 and 12 months of age. During this period, the skull is growing rapidly and the bones are still highly malleable, allowing a well-fitted helmet to guide growth toward a more symmetrical shape with the best possible results and in the shortest treatment time. Starting at 4–6 months generally produces the fastest outcomes. Treatment initiated between 6 and 10 months can still achieve excellent results, though it may take a bit longer. After 12 months, the rate of skull growth slows considerably, and while treatment is still possible up to around 18 months, the results may be less complete. This is why we encourage parents not to "wait and see" beyond the 4-month mark if a pediatrician has flagged moderate or severe asymmetry.
The typical duration of cranial helmet therapy ranges from 2 to 4 months, though this depends on the severity of the asymmetry at the start of treatment and your baby's age. Babies who begin treatment at 4–5 months with mild-to-moderate plagiocephaly often complete treatment in as little as 6–8 weeks. More severe cases, or those beginning treatment closer to 10–12 months, may require the full 4 months or slightly longer. Helmets are worn 23 hours per day to maximize the time spent gently redirecting skull growth, with one hour off each day for bathing and skin checks. Your orthotist will schedule regular follow-up appointments — typically every 2 to 4 weeks — to assess progress and make small adjustments to the helmet as your baby grows.
Insurance coverage for cranial helmets varies widely by plan and state. Many private insurance plans do provide coverage — particularly when a physician has documented moderate or severe plagiocephaly and medical necessity has been established. Medicaid coverage also varies by state. At Cranial Center, our team will work with your insurance provider on your behalf to determine your specific benefits, submit the necessary documentation, and help you understand any out-of-pocket costs before you make any decisions. We encourage you to come in for a complimentary consultation first — that way, if treatment is recommended, we already have the clinical measurements to support an insurance submission.
Mild cases of plagiocephaly can sometimes improve significantly with consistent repositioning and tummy time, especially when addressed in the first 2–3 months of life. As babies gain more head control — typically around 4 months — they naturally begin shifting their own position more, which can also help. However, moderate and severe cases rarely self-correct to a symmetric head shape without additional intervention. Studies that have followed untreated moderate-to-severe plagiocephaly over time show that while some spontaneous improvement occurs, residual asymmetry frequently persists into childhood and beyond. If repositioning alone has not produced noticeable improvement within 4–8 weeks, or if your baby's asymmetry is significant from the start, a professional evaluation is the best next step.
These are two very different conditions that can look similar to a parent's eye, but have distinct causes, presentations, and treatments. Positional plagiocephaly is caused by external pressure on a normal, healthy skull — the sutures (the fibrous joints between skull plates) are open and functioning normally. Craniosynostosis, by contrast, is a medical condition in which one or more of these sutures fuse prematurely, restricting skull growth and potentially putting pressure on the developing brain. Craniosynostosis typically requires surgical correction and is treated by a pediatric neurosurgeon or craniofacial surgeon — not a cranial helmet alone. A pediatrician or cranial specialist can usually distinguish between the two through physical examination, and imaging may be used to confirm. If there is any doubt, your doctor will refer your baby to the appropriate specialist. At Cranial Center, we screen for signs of craniosynostosis at every consultation and will always refer you to the right resource if we have any concern.