Plagio / Brachycephaly
About 15%* of all the babies develop a skull deformation during their first year since the prevention of sudden infant death syndrome. This is about 96.000 babies annually, in England alone.
The main cause of is the preferred position, which is created and maintained by sleeping and playing on the back. Lying on one side of the head for a long duration of time inhibits growth in that place. This is how the postural plagiocephaly or brachycephaly can develop.
* Deformational Plagiocephaly: A Follow-Up of Head Shape, Parental Concern and Neurodevelopment at Ages 3 and 4 Years