Hi I Have Tried Iui Twice Last Year Got Pregnant

hi I have tried iui twice last year got pregnant but had miscarriage at 8weeks this year we tried again every test was better and had more follicles and they where bigger this round the difference this round I had to drink Gatorade to prevent hyperstimlation and I cramp during the iui and before when I was taking the shots follistim and ovidrel and I don't understand why the iui didn't work this round