My daughter has had issues sleeping flat on her back, swaddled or not. We found out about 4 weeks in that she would sleep great in her swing or bouncer; I think she enjoyed the "cocooned" feeling. We've finally been able to all get decent sleep with her in the swing, but she's starting to get too long for it. She squirms and within an hour or so her feet are hanging off the end of the swing! I've been staying up watching her and scooting her up.