Plagiocephaly research summary

It’s very common for babies to develop a flat spot on their head (positional plagiocephaly), especially now that we place babies on their backs to sleep. The good news is that most mild flat spots improve on their own with simple measures like repositioning and tummy time.

A helmet is not needed for every baby. Research shows helmet therapy is most helpful when:

• The head shape difference is moderate to severe
• The flat spot has not improved with repositioning or physiotherapy

Doctors measure head shape using specific measurements (such as cranial vault asymmetry). In general:

• Mild cases usually improve without a helmet.
• Moderate to severe cases may benefit from helmet therapy, especially if improvement has stalled.

Studies show that when used appropriately in moderate-to-severe cases, helmets can successfully reduce asymmetry to mild levels in up to 80–85% of babies (Tamber et al., 2016; Kim et al., 2024).

While one study suggested helmets may not always outperform repositioning, most non-randomised research shows that helmets can lead to faster and greater correction in babies with more significant flattening.

If a helmet is needed, timing matters.

Babies’ skulls grow very quickly in the first year of life. Helmet therapy works by gently guiding this natural growth. For this reason:

• Best age to start: 4–6 months
• Effective window: 4–9 months
• Less effective after: 12 months

Starting earlier generally means:

• Better correction
• Shorter treatment time
• Higher chance of normal head shape

Success rates can drop from around 80% in babies under 6 months to 40% or less after 8–12 months, particularly in more severe cases (Kunz et al., 2017; Kim et al., 2024).

That said, improvement is still possible in older babies — especially in more significant cases — but results may not be as strong.

Research consistently shows three main factors influence how well helmet therapy works:

Age at the Start of Treatment

Earlier is better.
Each month of delay reduces how much correction we can expect, because skull growth slows over time (Kim et al., 2024; Kunz et al., 2017).

How Severe the Flattening Is

• Moderate cases tend to have the highest success rates (around 90%).
• Severe cases can still improve significantly, but may need longer treatment and are less likely to achieve complete correction.

Interestingly, more severe cases often show larger measurable improvement — but may not reach “perfect symmetry.”

Helmet Wear Time (Compliance)

Helmets only work if worn consistently.

• Recommended wear time is usually 23 hours per day
• Babies wearing the helmet more than 15 hours per day have much higher success rates
• Poor compliance is strongly linked to reduced improvement (Kim et al., 2024; Hauc et al., 2023)

Consistency really matters.

• Most mild flat spots improve without a helmet.
• Helmets are most helpful for moderate to severe cases that don’t improve with repositioning.
• Starting between 4–6 months gives the best results.
• Early referral, appropriate severity, and good daily wear are key to success.

If you’re unsure about your baby’s head shape, early assessment is helpful. Even if a helmet isn’t needed, we can guide you through positioning strategies and monitor progress.

You’re not alone — and in most cases, outcomes are very positive.

If you’ve looked into treatment for plagiocephaly, you may have noticed that the research can seem mixed or confusing. A few key points can help make sense of it.

Helmet Studies Have Limits

Helmet therapy is hard to study using “gold standard” research methods. Because helmets are visible, families know whether their baby is wearing one, which makes fully controlled trials difficult.

As a result, helmet research is often considered lower-level evidence — not because it’s poor quality, but because of practical limitations. This means findings need to be interpreted with care.

Helmets Aren’t All the Same

There are many different helmet designs, and these differences matter.

Design can affect:

• Comfort
• Skin tolerance
• How long babies are able to wear the helmet each day
• Overall results

So when reading studies, it’s important to remember that results may not apply to every type of helmet.

Evidence Needs Context

Research doesn’t always give clear yes-or-no answers.

Studies vary in:

• Baby age
• Severity of head shape difference
• Definitions of “success”
• Wear time

That’s why professional interpretation is so important. A health professional can explain how the research applies to your baby and help guide decisions using both evidence and clinical experience. Research is a valuable guide — but the best decisions come from combining evidence with individual assessment and family support.

• Tamber, M. S., et al. (2016). Congress of Neurological Surgeons Systematic Review and Evidence-Based Guideline on the Role of Cranial Molding Orthosis (Helmet) Therapy for Patients with Positional Plagiocephaly.
• Kim, J., Kim, J., & Chae, K. Y. (2024). Effectiveness of Helmet Therapy for Infants with Moderate to Severe Positional Plagiocephaly. Clinical and Experimental Pediatrics, 67(1), 46–53. https://doi.org/10.3345/cep.2023.00626
• Kunz, F., et al. (2017). Head Orthosis Therapy in Positional Plagiocephaly: Influence of Age and Severity of Asymmetry on Effect and Duration of Therapy. Plastic and Reconstructive Surgery, 140(2), 349–358.
• Hauc, S. C., et al. (2023). Predictive Factors of Outcomes in Helmet Therapy for Deformational Plagiocephaly and Brachycephaly. Journal of Craniofacial Surgery, 34(1), 231–234.
• Blanco-Diaz, M., et al. (2023). Effectiveness of Conservative Treatments in Positional Plagiocephaly in Infants: A Systematic Review. Children, 10(7). https://doi.org/10.3390/children10071184