This is how flattening occurs. It has nothing to do with a "soft" head or that the bones are malleable. It is exclusively a result of growth displacement around a point of contact. Newton's Law (equal and opposite forces) predicts that the force (weight X gravity) applied by the infant's head to the bed is met with an equal upward force from the bed to the head. This pressure restricts growth in the area of contact and growth is displaced to any area where there is no contact. As the head grows and increased in weight, this process actually accelerates. This is why flattening really explodes between 6-8 weeks in prone kids. As long as the head contacts the bed in the same spot, this process will continue. This is effectively a race between resolution of torticollis and head flattening. If the torticollis is mild, and motor development is normal, this process may stop quickly as the child begins to move the head more freely and redistribute the point of contact to other areas of the posterior cranium. The goal of redistributing pressure to multiple areas and not just one is the whole basis for reposition efforts, physical therapy, and tummy time (attempt to accelerate the development of motor control). For kids with more severe torticollis, or with developmental delays, this process can continue much longer and result in significant degrees of flattening. Moreover, these infants will not respond to repositioning and tummy time as well as the first, more mild, group. It is very hard to predict this up front who is who and that is why what works for some families (repositioning, TT, PT) may not work for others. There are many parents in this group that have done all of these modalities only to find that their child's head continued to worsen. It is not that they did it wrong or did not follow instructions. Instead they are fighting a very different set of circumstances. I have 4 children and never did anything to reposition or try to prevent head flattening. My kids never developed any flattening. Why? None of them had torticollis and all were developmentally appropriate for their age. My two brothers each had children who became flat in infancy. The difference? They had torticollis and I could see that from day one. Neither of my brothers listened to my concerns and after 3 months, both of their kids had varying degrees of head flattening. If you can identify a head rotation preference and/or lower motor control in an infant, you can predict their risk for flattening. Unfortunately, the pediatric community is not especially good at that.