baby getting arm stuck in crib ! crib bumpers?

My baby is a belly sleeper and a scuttlebutt! Whenever she sleeps she always manages to scoot herself all over the crib. Well lately, shes been scooting herself to the edge of the crib & getting her arm stuck between the crib bars - which then wakes her up. I know crib bumpers are not recommended, but what can I do to prevent her from getting her little arm caught in the crib bars? Thank you for any suggestions!