oops! I e-mailed you before I read down the list. I haven't been able to get on MDC until now and this post was a little ways down. Anyway, I am afraid I won't be much help. I'm a lesbian, so I did donor IUI by necessity
We went through a women's clinic. I'm not using any drugs or infertility treatments, and the clinic is staffed by non-medical personnel trained to do the procedure, so the breastfeeding thing never even came up. Sorry! I don't know what that does to your system if your going to take fertility drugs and bf. I do know that both I and a friend of mine got pregnant the first try with our IUIs and both of us were bf, so it's possible. Good luck!