I'm 20weeks with my first and have been advised to try out some slings now before my bump gets too big.
I have no idea where to start 
The things it think I have to take into account are:-
- It needs to be suitable for me and DH. I'm 5'1 he's 6'2
- I am very well blessed in the chest department, without being pregnant!
- I have issues with a reoccurring injury in one shoulder that may be aggrivated by a sling but I don't know.
- We need to be able get baby in or out without assistance.
Oh wise MNetters help me out please!!! :o