Head Flop vs. Upper Body Disproportion – only one kills

Head Flop vs. upper body disproportion


Head Flop vs. Upper Body Disproportion (2)

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It goes under numerous names; head flop, head drop, head loll, head this and head that. And did you know that it’s an extremely common thing to happen to children in car seats? Did you also know that this is actually not a medical safety concern for healthy children over 6 months old?

Many parents worry a lot when they see a “head flop” on their children. It could be that they are worried about breathing issues to just normal comfort issues – and that is why I’m writing this post. To try and go into a little detail about this “issue” and why it’s actually NOT an issue at all and nothing to worry about.

Head flop is something that can happen in all car seats from rear facing infant car seats all the way up to the high back booster. And it can also happen to all ages of children and it’s not something that is specific to any type of brand car seat.

So why is it that parents are so worried about these things? 

Well for starters I think the media has a lot to do with it. We are far too often bombarded with news headlines of babies who have died in a car seat – which is a tragedy, but it’s not a common issue (thank goodness) and by following general safety advice we can reduce the risks as much as possible.

Please read my post about the 90 min rule which goes into detail on this topic. 


The likelihood of head flop to happen increases if the car seat is not used correctly, so the first thing to check is whether or not your child is strapped in correctly.


4 Steps to securing your child in their car seat correctly-


Despite following these steps though, head flop can still happen. Anecdotal evidence shows it to be more common in ISOfix car seats (Group 0+ & 1 ) than seat belt fitted car seats. The reason being that you can’t play with the recline of a car seat that uses ISOfix to install – but you can do this with a seat belt installed car seat with tethers.


What other factors can be in place? 

The slope of your vehicle back seats can also be a big factor to whether or not you would have a “head flop problem”. Especially with ISOfix seats. And also where the ISOfix connectors are located in the vehicle – if they are high or low. BeSafe reported that you can find as much as a 13-degree difference in recline on the same car seat depending on what car it’s installed in because of the slope of the back seats.

Never the less even taking these factors into consideration, as I mentioned earlier this can happen to children of all ages but is only dangerous if a baby is under 6 months old or there is a medical issue related to breathing.

NB! If your child has special needs or medical related issues please contact a specialist like In Car Safety Centre for advice on car seats that will fit your child and your child’s needs. 

What if my baby’s head is flopping and he is under 6m old?

  • Baby’s head flopping to the side = OK
  • Baby’s head flopping down towards his chest = NOT OK. 

Sometimes head flop happens in infant car seats that are on a base – especially if your back seats are sloped, so my advice is always to try to install the car seat without the base and see how that goes as well as positioning baby properly in the seat. (See my tips earlier in the post)

Products to help head flop?

If you have followed the correct steps to make sure your child is correctly seated in the car seat and you are still getting head flop, being it in the car seat or in a high back booster there is another option I want to mention.

It’s a product called the Trunki Yondi. And it’s suitable for children aged 2 years and up (but you can use it for younger children if it still fits correctly). It is also usable in a high back booster.

Yondi has been carefully designed so as not to interfere with the child’s position relative to the back and wings of a car seat. Yondi should not affect the way the car seat performs or increase the risk of injury in a crash.


Trunki Yondi in use
Logan sporting the Trunki Yondi in his Britax Two Way Elite.

Trunki Yondi is tested to EN71 standard Part 1, 2 and 3. The materials have also been tested for Azo dyes, Phthalates, Cadmium and Formaldehyde.

So now that we have covered ‘head flop’ let’s move over to what is actually dangerous; Upper Body Disproportion. 

As I mentioned earlier in the post – there is a big difference between this and head flop – though many tend to call them the same so I am now going to try to explain the difference.

When a child has an “upper body disproportion” in the car seat, that means that the child’s whole upper body is no longer positioned correctly in the car seat. He is slouching forwards or sideways and is now outside the protection of the seat. There can be severe incidents of this and there can be the smaller incidents of it – but all in all, it’s something to be avoided.

Caitiebelle sporting a dangerous upper body disproportion in her car seat
Caitiebelle sporting a dangerous upper body disproportion in her car seat. This was resolved by simply re-installing the car seat in a more reclined position.


As with head flop, this is generally avoided simply by making sure the child is correctly seated in the car seat (see the beginning of the post for my tips). So the first step to avoid it – is to make sure your child is actually seated correctly.

The problem can occur in both car seats and high back booster car seats. If this is happening to your child in a high back booster car seat you could look into getting a HBB that offers a slight recline or “snooze mode” as some HBB can be very upright in the back.

Make sure that your child is correctly fitted in the high back booster and that the seat belt is correctly fitted on the child and pulled tight and also be aware that children under 4 years old should stay in a harness if possible! If your child has reached the max weight limit of their previous car seat there are other car seats available that harness all the way up to 25KG/55lbs.

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At times it can be the seat itself that is the problem, and sometimes it can be the seat, the install AND the incorrect fitting of the child that is the problem. This is why it’s so important to make sure that we strap the children incorrectly in the seats.

Below is an example of a small baby with ‘upper body disproportion’. But what I also notice is that it is possible that it could be avoided if the harness straps were at the correct level (they should be just at or just below the shoulders) and the full baby insert was used, but I would also like to say that the car seat used is really not suitable for so young infants and I would def. say to avoid them:

Source: http://tinyurl.com/z86b4c8


What are some of the dangers for my child if they have ‘Upper Body Disproportion’?

If we try to only look at the older harnessed children first and not the babies – since I covered them above, because the babies are smaller and won’t be hanging much out of the seat at all, there are a few key dangers to be aware of.

When your child isn’t correctly positioned in the car seat – but hangs out of it or hangs out of the protective sides of the car seat, this increases the risk of injury to the child, especially in a side impact collision. During a frontal impact the child, if in a rear facing car seat, will still move back towards the back of the car seat even if they have some upper body disproportion (which will then put them back into the seat’s security) – however as we can not know beforehand what kind of accident we will have, I always advice to just avoid this problem all together and sort it as soon as possible.

For a forward facing child, it becomes even more important to make sure their whole body is correctly seated in the seat and making sure they are not leaning forward into the deployment path of an airbag.

In a side impact collision, the child’s disproportion out of the protective shell of the car seat can have major consequences to their head and upper body.
These dangers are, but not singularly restricted to:

  • Curtain airbags and other side impact protecting airbags (SAB) not inflating properly on impact, thus not giving the important SIP (side impact protection) they are meant to give.

ROSPA says: Side airbags are usually a curtain airbag which deploys downward to provide protection to the head and are not as powerful as the front ones. They should not pose a risk to a child in a child seat in the rear, but provide added protection.

Make sure that the child seat is fitted properly and your child is using it correctly. Try to prevent the child seat leaning close to, or against, the door or window. Of course, children often fall asleep in child seats but seats with side wings will help to stop a sleeping child’s head resting against the side window.

If concerned, contact the vehicle manufacturer to ask how far the side airbags come out if they deploy and whether they are likely to contact a child restraint in the rear outboard seats. EuroNCAP tests include assessing the safety of child seats in a side impact, so check www.euroncap.com to see if your vehicle model is one of those that has been tested.

Please note that SABs (side airbags) are perfectly safe for children both in and not in car seats when they work correctly!
(Also note that you should never install a rear facing car seat in the front seat where there is an active airbag as this is a great fatality risk!) 

  • Side impact with a protruding door
  • Bigger chance of injury related to the vehicle’s interior
  • Higher chance of injury for the child because the child might be closer to the impact point



I hope you found this article helpful and that you feel you can relax more now if you see head drop in your child!

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  1. ROSPA: Airbags & Child Seats
  2. The Car Seat Lady articles: 1 2 3 4
  3. Car Seats for the Littles: Head slump, oh no! Or no biggie?
  4. BeSafe Norway
  5. The exposure of children to deploying side airbags: an initial field assessment.
    Arbogast KB1, Kallan MJ.
    1Center for Injury Research and Prevention, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
  6. Infasecure.com: Nodding off head flop
  7. Sudden unexpected infant deaths associated with car seats.
    Bamber AR1, Pryce J, Ashworth MT, Sebire NJ.
    1Department of Histopathology, Camelia Botnar Laboratories, Great Ormond Street Hospital for Children NHS Trust, Great Ormond Street, London
  8. Hazards Associated with Sitting and Carrying Devices for Children Two Years and Younger. (Article in press: HERE)
    Batra EK1, Midgett JD2, Moon RY3.
    1Departments of Pediatrics and Family and Community Medicine, Penn State Milton S. Hershey Medical Center, Penn State College of Medicine, Hershey, PA.
    2Office of Hazard Identification and Reduction, US Consumer Product Safety Commission, Bethesda, MD.
    3Division of General Pediatrics and Community Health, Goldberg Center for Community Pediatric Health, Children’s National Medical Center, Washington, DC; Pediatrics, George Washington University School of Medicine and Health Sciences, Washington, DC.
  9. UMTRI Research Review July-September 2000, Vol. 31, No. 3 
  10. Injury Prevention & Control: Motor Vehicle Safety


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