clare I wouldn't think so - although I have no professional knowledge - Jake was a very bad reflux baby and never did tummy time until he chose to once he started sitting up. Even then after a few minutes on his tummy he would scream the house down. As for his milestones his head raising ones were way behind initially but he was walking his trolley around at 9 months and now is fine. In my opinion they adapt to the situation. HTH to put your mind at ease.