When he gets overtired, the only place my little 3 week old boy will drop off is in his sling (fabric type affair, legs pointing down, body as upright as it goes!). Brilliant for me and for him, I get things done, he sleeps for hours at a time and wakes up chirpy. At night he is flat in his bedside crib and in the afternoon he often chills out in the pram. BUT my mother is convinced I am distorting his posture by letting him sleep in the sling like this - should I be concerned or is she worrying about nothing?!