Babies don't get plagiocephaly from being put on their backs to sleep but from spending extended periods lying on their backs, particularly if they always tend to lie looking to one side. This can occur because:
Tummy time is very important for any baby. While many babies don't like this position at first, you can encourage your baby by joining him or her on the floor, for playtime. Remember, babies only need to be on their back when sleeping!
"Ah! His head is flat!" I became obsessed. I went back and looked at pictures of Eli fresh from the womb. There he was with a perfectly round melon. I researched baby skulls and the malleability of the brain. I called our pediatrician and couldn't wait for a check-up.