I just wanted to clarify that in IVF without ICSI the sperm and the eggs are placed in a plastic dish with the hope that the next morning the sperm will have fertilised the eggs. The condition of the uterus is not a factor for ICSI as the fertilisation is done outside the uterus anyway. There is a plasma-based solution (I think - BW/BG??) that is in with the eggs/sperm which makes conditions good for making embies.
Kim, that's correct. Where the sperm sample in the dish (typically some tens of thousands) is judged to be normally motile and normally shaped, they are generally left to their own devices, unless the egg/s are know to have a particularly tough zona (exterior).

As for ICSI, it isn't really to do with the environment of the uterus (or vagina etc), as straight IVF overcomes any potential issues there.