DD is a side sleeper and always has been. When she goes over to her tummy, shes not too fussed and sleeps well. Except now, when shes on her tummy she tries to escape!! So its great.. until they start trying to crawl!! lol. Mia is the same if shes on her back, she rolls over within a second. I think she has slept on her back.. mayb 3 or 4 times since she was born and that was lie 1-2 weeks old!