The hospital where I had DD had 'wookies'...so if the mum and bubba was separated (ie - prem or sick) then bubba had one wookie and mum had the other, then when you see each other next you swap...
I don't know whether the whole scent thing worked as we were swapping them daily - but for me (as silly as this will sound) i felt the wookie 'was' my baby, until I managed to get her home from hospital 6 wks after her birth...It made me feel closer to her, even when I wasn't there.