How Long Does Flat Head Take to Correct? (What Studies Say)

Your baby, a few months old (or more!), has a flat head, and you’re wondering until what age it will last? And does it depend on things to implement?

As a physiotherapist, I am regularly approached by concerned parents about this. Here is a summary of what I think is important to know about the evolution of plagiocephaly or brachycephaly.

I rely on my experience as a physiotherapist and international medical knowledge (references to scientific publications at the end of the article).

Happy reading! Any questions or comments? See you in the comments 🙂!

Summary: 3 out of 4 babies still have a slightly flatter head than the norms after the age of 2. But since this concerns a lot of children (1/4 to 1/2), maybe these norms need to be reconsidered?”

Reminder on the different types of flat heads and causes

First, let’s agree on what we mean by a flat head!

It is the fact that babies often have the back of their head or one side of the skull slightly flattened.

In medical terms, we call it:

• Plagiocephaly: one side of the back of the skull is flatter than the other.
• Brachycephaly: the head is flattened symmetrically on both sides.

Flat head = plagiocephaly OR brachycephaly

There are two origins of plagiocephaly/brachycephaly.

By far the most common, positional plagiocephaly or brachycephaly.

This is what we will talk about here. It is thought to be due to:

• the fact that babies are often on their backs, the head against something hard;
• the use of forceps or vacuum during delivery;
• sometimes, congenital torticollis.

And the (much) rarer one, due to craniosynostosis.

When a flat head is due to craniosynostosis, the treatment is different: it often requires surgery. It is due to a combination of genetic and environmental factors.

If your baby has a flat head, it is much more likely to be a positional form, not craniosynostosis.

Because:

• craniosynostosis affects 3 to 6 births out of 10,000 (Cornelissen 2016);
• positional plagio or brachycephaly: 1 birth out of 4 to 1 birth out of 2! (DiRocco 2019, Ellwood 2020)

How do we know until what age a baby’s head is flat?

There has been an increase in babies with brachycephaly or plagiocephaly since it was recommended to make babies sleep on their backs (to prevent sudden infant death syndrome).

Pediatricians and doctors have conducted studies to measure this phenomenon. In some maternity wards or health centers, babies with or without a flat head have been followed for several years to assess their evolution:

• does a flat head appear?
• At what age, on average?
• When does it disappear?

I rely precisely on the results of these studies to give you the most accurate estimates possible of how long does it take for plagiocephaly to correct itself.

Until what age is a baby’s head flat?

Here are the results of a study (Van Winjk 2014) that followed 84 children diagnosed with moderate or severe plagiocephaly or brachycephaly between 5 and 6 months.

These children were followed for several years: some did not receive any particular treatment, others had physiotherapy sessions, and others had an orthopedic helmet for the flat head.

• At the age of 2 and a half, 1 in 4 babies had a completely round skull
• The other babies (3/4) have a skull that has rounded but is not yet completely within the norms
• The evolution is the same whether the babies wore a helmet or not.

Do you think that 1 in 4 babies no longer having a flat head at 2 years old is not much? This is what the authors of this study conclude:

We can always wonder what is an acceptable head shape in young infants and at an older age when the head is covered with hair.

Van Wijk 2014

In other words, since 1 in 4 to 1 in 2 babies has a “flat head,” we can ultimately wonder if it makes much sense to focus on these indicators. Because as a baby grows:

• their hair grows and masks the shape of the skull;
• their head becomes smaller in proportion to the rest of the body.

It is also reasonable to think that after 2 years, the skull continues to round in children who have not yet regained a very rounded shape.

What to do to limit the flattening of a baby’s head?

As a parent, you can do at least 3 things if you notice that your baby’s head is flat:

1. seek the advice of your general practitioner or pediatrician to objectify plagiocephaly or brachycephaly and rule out craniosynostosis as the cause (which is generally visible at birth and, as a reminder, is very rare);
2. implement certain daily habits to limit the accentuation of the flat head. A pediatric or general physiotherapist can provide personalized advice on this subject (see also this article on baby motor skills);
3. implement a more specific treatment: physiotherapy sessions and/or an orthopedic helmet.

General advice for those caring for the child

Here’s what you can do to limit your baby’s flat head.

The idea is to vary your baby’s positions and limit, when possible, lying on their back on a hard surface (especially in the car seat).

4 tips:

1. When your baby is awake, regularly place them on their stomach (tummy time) to avoid prolonged contact of the back of their head with the floor, which could increase the risk of flattening the skull.
2. Also, vary their position by putting them on their back, on their side, in a bouncer, in an adapted chair, carried in a baby carrier or a sling, on your knees, etc., and on different surfaces like a mattress on the floor, in a playpen, or in a bed.
3. If you notice that your baby turns their head more often to one side than the other during their waking or resting times, adapt their environment to encourage them to look to the other side. For example, position yourself on their right when you speak to them, place toys at a height to the right, direct the light source to their right, feed them by positioning yourself on their right, etc.
4. Avoid leaving your baby in the same car seat for long periods. If you use a car seat, make sure to carry them in a baby carrier or sling when you get out of the car, or use a bassinet or a stroller suitable for their age. This will help distribute pressure points on their skull.

Regardless of the measures taken, it is strongly recommended to make your baby sleep on their back. This position is associated with a significant decrease in the risk of sudden infant death syndrome.

Physical therapy or orthopedic treatment with a helmet

Some people feel the need to do more against flat head than these common-sense tips. Here is a summary of possible options. You will find more information in my dedicated article on the treatment of plagiocephaly and brachycephaly.

Treatments	Theoretical Effectiveness	Theoretical Side Effects	Empirical Effectiveness	Cost (Time/Energy/Money)	Therapist Dependence	Equipment Dependence
Change baby’s position often	Yes	Low in theory	?	Free	No	No
Specific exercises	Yes	Low in theory	?	Yes	No	No
Physiotherapy	Yes	Low in theory	?	Yes	Yes	No
Osteopathy	No	Low in theory if gentle maneuvers	No	Yes	Yes	No
Helmet	Yes	Yes	No	Yes +++	Yes	Yes
Positioning cushion	?	Yes	?	Yes	No	Yes