If they are strong enough to roll over then you don't have to worry about it cause they can lift their head. All of mine have done that and I just leave them once they roll over.
Once they start to roll over..not much you can do
Just peek in on them i guess..
I agree with Shedevil - My dr told me that - Once they roll there is not much you can do. To put your mind at ease though -BOTH my babies slept on thier tummies and they were fine. I HONESTLY feel that MOST SIDS cases are either from abuse or an underlying problem that goes undetected but I could be wrong that just MHO. If your baby is comfy and sleeps let her go and you try to rest also. Good Luck and try NOT to worry (I know easier said than done LOL!!!!!)
I usually let her nap on her tummy when I am awake but at night is when it makes me nervous.
I never realized how crazy I would be as a Mom. We waited 10 years for her.
Yeah, I don't think there is much you can do once they start the rolling. Just keep the crib uncluttered, and avoid really cushy things. My kids are 9 & 7 and I still check on them when they sleep!