Hi, I have quite alot of experience with flat head as my son has it and is currently wearing a cranial helmet.
My LO is 7 months old and was born 6+ weeks premature. I didn't actually notice his head going flat at first, it was only when my Mum mentioned it going flat I realised there was a problem. Within a space of 2 weeks it was completely flat at the back.
I done alot of research into flat head and the more I read, the more I became concerned. I spent alot of money on a CO and I have to say it made no difference at all, although some people swear by it so I would never rule anything out! I tried the pillows, aggressive repositioning but it was too late and made no difference. Repositioning is great if they are only a couple of months old. After 5 months it seems it's unlikely to make much of a difference.
I took him to LOC clinic and he was then diagnosed with extremely severe brachycephaly and is at the high end of the severe bracket. I've had so many tears and nights of worry about considering the helmet but all I can say is it is the best thing I have ever done. My LO had a growth spurt in the first week of wearing it and his head is amazing in the 5 weeks it's been on. We have a long way to go yet but I know his head will be ok. What helps is that he isn't bothered by it in the slightest - it was me that had the problem.
I still have a very content, happy little boy who will now have a 'normal' shaped head at the end of treatment. I worried not only for the shape and him perhaps being bullied at school for it but also the development issues that come with flat head as there is a big question mark over this (eyesight, hearing, jaw problems and not to mention ADHD etc). To me it was a no brainer.
Sorry to go on, I just wanted to share my story of a little boy who has flat head. All I can say is how important it is to reposition them, tummy time as much as possible - atleast 2 hours a day apparently. This doesn't mean being on a floor on a mat all the time but put LO on your tummy aswell and superman around the house! Everything you can to use their neck muscles. The pillows are great if they are young enough and also the sleepcurve mattress. I just wish someone would have talked to me about flat head earlier to save such alot of heartache and money.
x