Brachycephaly in Babies: What Is Flattening of the Back of the Head?

Brachycephaly in babies describes flattening that parents often notice on the back of a newborn’s head. If, when you hold your baby or look from above, the back looks flatter than expected and the sides look wider, brachycephaly may be present. It is a common shape difference worldwide and in Türkiye, and it can often be managed when recognized early.

What Is Brachycephaly (Flattening of the Back of the Head)?

Brachycephaly comes from Greek roots meaning “short” (brachy) and “head” (cephal). It is symmetric flattening of the occipital (back) region with widening toward the sides. While plagiocephaly is asymmetric, brachycephaly in babies usually appears as even flattening.

It can increase apparent head height and make the head look wider above the ears. Parents often say, “the back of my baby’s head looks very flat.”

What Causes Brachycephaly?

Infant skulls remain soft and flexible after birth to protect a rapidly growing brain and to allow passage through the birth canal. That flexibility also makes the head more sensitive to external pressure. Common contributors include:

• Back sleeping: The 1990s “Back to Sleep” campaign greatly reduced Sudden Infant Death Syndrome (SIDS). Continuous back lying, however, increases pressure on the occiput and can raise the risk of back-of-head flattening.
• Larger head size: Some babies have genetically larger or heavier heads and may struggle to turn side to side, preferring to rest fully on the back.
• Low amniotic fluid: Reduced space in the womb can restrict movement and create pressure on the back of the head.

How Can You Spot the Signs?

Simple home observation can raise awareness, but definitive assessment needs a clinician.

• From above, does the head look more “round” or “square” than egg-shaped?
• Does the back of the head drop straight down?
• Does the rear crown look higher than usual?
• Is width above the ears greater than expected?

Supportive Methods and Helmet Therapy

In mild cases, supervised tummy time while awake and varied sleep orientation (with clinician guidance, always keeping safe back sleep) can help. In moderate to more advanced brachycephaly, positioning alone may not be enough.

This is when a cranial orthosis—helmet therapy—may be discussed. The helmet gently guides growth from wider sides toward the flatter back. It is passive guidance, not forceful compression. The HKM Pro cranial helmet is fitted only at CranioWell Orthotics & Prosthetics Centers.

At CranioWell, we measure your baby’s head with 3D scanning and discuss a suitable plan. For details, contact us via our Contact page.

Frequently asked questions

Does brachycephaly cause developmental delay?

No. Brachycephaly is a deformational shape difference of the skull, not a neurological disease that directly affects intelligence.

When does back-of-head flattening improve?

When babies start rolling and sitting (around 6 months), pressure decreases. Mild cases may improve then. Intervention before bones harden (within about the first 18 months) remains important when concerns persist.

Will helmet therapy bother my baby?

Modern cranial orthoses are lightweight and ventilated. Many babies adapt within 1–2 days and continue daily activities.

Summary and Recommendation

If you wonder whether flattening on the back of your baby’s head is temporary or needs care, seeking specialist input sooner is wiser than waiting. At CranioWell Orthotics & Prosthetics Center, a preliminary evaluation can measure cranial index and clarify next steps.

Legal note: This content is for information only and does not replace professional medical advice or diagnosis. Please consult your physician for health concerns.