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What is Flat Head Syndrome in babies & what causes it?

by BabyYumYum
Baby Yum Yum - What is Flat Head Syndrome
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Does your baby have a flat head? There are an increasing number of parents presenting at paediatric healthcare centres with concerns about the shape of their child’s head.

In my consulting room I do sometimes notice a raised eyebrow from the grandparents when we start to discuss “Flat Head Syndrome”. It is not a concept that grandparents would have encountered if their own children were born before 1992. Let’s explain why.

Baby with a flat head

In 1992, the American Academy of Paediatrics (AAP) began a campaign called “Back to Sleep”. The campaign was aimed at reducing the number of Sudden Infant Deaths (SIDS). This campaign urged all parents to place babies on their backs when asleep.

Since the start of this campaign there has been a significant decrease in the number of deaths due to SIDS but another problem has raised its head. Apologies for the pun but infant plagiocephaly and brachycephaly (DPB) and congenital muscular torticollis (CMT) has been on an upward spiral since the “Back to Sleep” campaign began.

Why does my bay have a flat head & should I be worried?

What has been noted is that babies are spending both sleep and awake times in reclined positions on their backs, be it in a cot, pram, bouncy seat, swing or car seat.

Due to our busy lifestyles and a baby’s objection to tummy time, babies spend too much time in one position and this affects the shape of the head.

causes flat head syndrome in babies: doctor measuring a baby's head

Does having a flat head affect a baby’s development?

While there are articles claiming that the shape of the head does not affect a baby, more recent studies call on practitioners to be aware that these conditions may be linked to a child’s ability to meet certain neurodevelopmental milestones.

Whether the baby’s flat head causes the neurodevelopmental delays or whether a child with developmental issues is less likely to move its head freely, thereby causing the flat head, is still being debated.

Let’s understand some of the terms used when considering the shape of a child’s head before moving onto the other causes, diagnoses, possible effects and treatment options.

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What you need to know about Flat Head Syndrome in babies

The most common term used is Flat Head Syndrome but in relation to this condition you may come across other terms such as:

Plagiocephaly (DP)

This term refers to a head which is flattened on one side.

The face often appears asymmetrical with one ear being more forward than the other on the head. The eyes are not lined up straight. The face and forehead may bulge a little on the side where the head is flattened.

Brachycephaly (DPB)

This term refers to a baby’s head that is flat at the back.

It usually causes the head to widen. Imagine a pumpkin lying on the ground. The under surface of the pumpkin doesn’t become round because of the hard soil. The pumpkin flattens underneath and bulges out on the sides.

A baby’s head responds in the same way as the pumpkin if it is allowed to lie on a solid surface for long periods of time. The back of the head flattens and the forehead may bulge.

flat head syndrome in babies diagram

Via choosept.com

Congenital muscular torticollis (CMT)

This refers to tight or shortened neck muscles. The muscles on one side of the neck may be tighter than the other leading to a child favouring one side of the head to the other.

You know what it is like to wake up in the morning with a stiff neck. We naturally guard the side which is stiff and try to only move the other side. Babies born with CMT will usually only feed from one breast, avoid turning their heads to look around and favour lying down with their heads facing in one direction.

All of these factors will make the baby more likely to face in one direction and this will affect the shape of the head.

What causes Flat Head Syndrome (DP and DBP) in babies?

There are a number of causes of Flat Head Syndrome in babies, and we’ve already mentioned two of them:

Sleeping on their backs (supine sleep position)

We have to put babies to sleep on their backs but studies have shown that 20 to 25% of babies who sleep on their backs develop brachycephaly to some degree or another. This doesn’t mean parents should allow the child to sleep in any other position but should encourage other head positions when baby is awake.

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Muscular torticollis

The head tilts in one direction because the muscles of the neck on one side are shortened.


These babies have very soft skulls and generally spend time in a neonatal ICU. They spend a long time on their backs, especially if they need to be ventilated. This will cause the back of the head to flatten.

It is interesting to note that during COVID times, the number of premature babies suffering from this condition increased substantially. During this time visiting was restricted so it was less likely for the baby to be held by parents and grandparents – when a baby is held in someone’s arms, pressure is taken off the back of the head.

Inadequate space in the womb

A mother may have a small womb and this could put pressure on the head before baby is born.

This is also often the case in multiple births. If two or more babies have to grow inside a tummy there is less space than in the case of a single baby.

Where there is too little amniotic fluid in the womb, the head may be squashed against the womb because there isn’t water to cushion the head.

Prolonged labour or assisted birth

A baby that is in the birth canal for an extended period of time may well experience a lot more pressure on the head and this may lead to flattening in the area of most pressure.

In cases where instruments are needed to deliver the baby, the baby’s skull may be affected by the pressure applied to pull the baby out of the mother’s pelvis.

ALSO READ: Diagnosing Flat Head Syndrome in babies & treatment options


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