Just wanted to add....I didn't trigger for my IUI, I used opk's because I ovulate on my own. So my IUI was around my normal ovulation time -CD15-16. I was told that we would have an IUI after my 1st positive opk, but I went in that morning for an u/s and I hadn't ovulated. My doc said that the sperm have a shorter life because they are stripped from seminal fluid....so they prefer to do the IUI after confirmed ovulation. She said they have pretty good success doing it that way. My IUI was done 48 hours after my 1st opk.
This is my first IUI cycle....I sure hope it works the first time