What Is Brachycephaly and Why Does It Happen? | CranioWell

• What is brachycephaly?
• Why does brachycephaly happen?
• Most common causes
• Positional causes
• Positional pressure during sleep
• Congenital causes
• Larger head size
• Prenatal and birth molding
• Oligohydramnios (low amniotic fluid)
• Evaluate your baby’s head shape – request a preliminary assessment

What is brachycephaly?

Brachycephaly (flat head) features a flattened area at the back of the skull with increased width. Many parents notice a brachycephalic shape around eight weeks, when the head looks wider than expected and the ears may be pushed outward. Keep reading to understand how this pattern is recognized.
Brachycephaly means a relatively wide, short skull (typically width at least about 80% of length).

In brachycephaly, the head is often taller at the back, and the occiput can look completely flat without rounding toward the neck. Brachycephaly is a form of flat head syndrome and can occur alone or with plagiocephaly. See also our article on brachycephaly signs for a practical checklist.
Parents who notice a flat area can find it hard to tell plagiocephaly from brachycephaly; prior CranioWell articles explain how the two patterns differ within flat head syndrome.

Why does brachycephaly happen?

Brachycephaly develops when natural head growth meets external pressure that slows expansion in that region. In early infancy the skull is soft enough for outside pressure to reshape areas and produce brachycephaly.
That pressure may begin before birth in the uterus or after birth from how the baby lies.

Most common causes of brachycephaly

Positional causes

Positional pressure during sleep

Babies are born with soft, flexible skulls. If your baby tends to sleep in the same position every night, ongoing pressure on the same area can flatten it. As the flat spot develops, the baby may settle into that position even more, or the head may naturally fall back to it.
This cause is common partly because of safe-sleep advice. Back-to-Sleep campaigns tell parents to place babies on their backs to reduce SIDS. Despite the rise in flat head syndrome, back sleeping remains a highly successful recommendation for reducing sleep-related death risk, and crib death rates have fallen substantially since the campaign began. For CranioWell guidance on infant head shape and safe positioning, see our repositioning guide.
Mild brachycephaly is often managed with repositioning; more advanced cases may include helmet therapy at CranioWell Orthotics & Prosthetics Centers.

Congenital causes

Larger head size

Some babies have larger heads than others, and a small infant’s neck muscles may not yet turn the head through different positions easily.

Prenatal and birth molding

A baby may be born with a brachycephalic shape because of position in the uterus or descent through the birth canal.

Oligohydramnios (low amniotic fluid)

When the amniotic sac does not contain enough fluid, intrauterine cushioning is reduced. Twins or other multiples can also create crowding. That prenatal environment can press on the skull and contribute to a brachycephalic shape.

If you suspect your baby has brachycephaly and want professional assessment, speak with clinicians familiar with cranial care or visit a cranial treatment center. See the CranioWell homepage for treatment and appointment information.