Sleeping on side?

I am putting Aleyna to sleep on her back but I just noticed she fell asleep on her side...she has done it twice today is that normal?

hey dilzy. Lochie has started doing that aswell. he seems to sleep better on his side. He goes to sleep in his cot on his side most of the time, he actually looks more comfortable this way. So i don't see a problem with it, I keep checking on him to make sure he hasn't rolled onto his stomach but like I said he seems to have better sleeps when he is on his side.