Flat Head Syndrome in babies is called either Posterior plagiocephaly, Nonsynostotic occipital plagiocephaly, Posterior positional plagiocephaly or Positional skull flattening.. Phew, what a mouthfull. So, what does it all mean?
A baby's head, as mentioned on the other pages, is very much like a balloon filled with water. This is good in most respects but it does mean that it is prone to moulding forces when it is placed up against something more solid, such as a mattress. When a baby sleeps their neck muscles switch off and that allows the head to roll, typically to the right. This, over time places pressure on the back right hand side of their skulls, and this in turn causes the skull to mould and change shape. Some considerable change in shape can occur, and although it is natural and not life-threatening it can have marked effects on such things as the development of the spine due to the twist this can create (known as torticollis). Due to the nature of the mechanics of the skull, if the skull flattens on i.e. the back right hand side the you will more often than not see a flattening of the opposite (front left hand) side when seen from above.
There are plenty of things that you as a parent can do to limit such changes, such as positioning your child in different ways in their cot when they sleep so that different parts of their head are resting on the mattress (but never face down or in any way against any of the guidelines on SIDS / cot death!!!). This can be done by propping them up ever so slightly on one side using a folded small towel or blanket. Change the side on which they sleep night by night to distribute the pressure. This can work well in the early months but soon the babies start to roll around and away from where you placed them. This is a positive step as it helps shift the pressure. Tummy time is very important because it develops the muscles of the neck and also reduces the amount of time the baby spends lying down. Other things that you can adjust your behavioral patterns. For instance, most people are right-handed which means that most parents carry their baby in the left arm (so that their right hand is free to perform tasks such a writing etc). This forces the baby to always turn their head the right so that they can look at their parents, which can lead to unequal muscle development. Similarly, most right-handed parent lay their babies over their left shoulder when trying to comfort or burp them, which again forces the baby to look to the right so that they can see the room. These un-equal muscle developments will tend to cause the baby's head to roll to the right when it is sleeping. Being aware of these habits allows you to change them, which will help in the prevention of any flattening.
More recently new baby "pillows" have hit the market. These pillows are made from memory foam or soft fibres that mould to the shape of the skull, so evenly distributing the pressure, thus potentially limiting the moulding forces. There are also head bolsters that seem to act to hold the baby's head balanced on the back of its head and not allow it to roll either way.
At the extreme there has been a move to use orthotic helmets to correct the flattening. These are in essence miniature bicycle helmets that are fitted such that they fit snugly around the part of the babies head that is "normal" but leave a gap where the skull has flattened. The idea is that as the skull grows it will push out into the gap and thus correct the deformity. They have to be worn pretty much constantly for extended periods of time. As they are relatively new to the "market" data about their efficacy is still being collected and I will report back when more studies have been conducted into their long-term use.
It is worth noting here that there is a serious complaint called craniosynostosis. Normally the joints of the baby's skull remain free and mobile, but very rarely they can fuse over. This results in unequal or distorted growth of the skull, depending on which joints are involved. The complaint is serious can can require surgical intervention to free off the joints to prevent possible brain compression and / or cosmetic changes. Surgery is very successful in the vast majority of cases but it is important to recognise this complaint for what it is, as opposed to some positional skull flattening. If you are in any doubt you should contact your doctor.