Babies with Flat Heads
I know waaayyy too much about this topic. When Avery was about 2 months old I noticed that her head was a little flat on the back right side. I also began to notice that she alway tilted her head the same way, no matter what we did to get her to look the other way. I asked the doctor about it at her next appointment and he said she ad Torticollis. Torticollis is basically really tight neck muscles on one side of the head. It's usually caused by being stuck in one position in the womb and is relatively common for first time moms who are on the smaller side. There just isn't room for the baby and their muscles develop all kinked up.
We started taking her to physical therapy to stretch the muscles out. The PT specialist immediately freaked us out by talking about how she might need to wear a helmet to fix the shape of her head. She said that the stretches will fix the torticollis but if she doesn't get off that side of her head the flattening could get way worse. If it got to the point where her jaw/ears became misaligned then she could have some serious issues growing up.
Because I stay home with her I had the opportunity to CONSTANTLY stretch her out and make her stay on her left side so her right side could round out. If she had been in daycare I doubt they would have had the time to do all that. We even started changing diapers with our left hands (which we still do now) just so she'd have to turn to her left to look at us.
All the hard work paid off in within 2 months we graduated from physical therapy with no need for a helmet. Now you can't tell there was any flattening at all!
My advice for new moms (and myself for our next kid) is this. Keep your kids out of cradling holders like car-seats and swings as often as possible. They restrict head movement and you want them to be able to turn their neck from side to side. This stretches the muscles and makes sure that they don't rest on one spot on their head all the time. Tummy time is also extremely important to build muscles and give the backs of their heads a break.