i have had my mirena for a year and half and i have learned you have to throw any expectations you have of your period to the wind
. i would get mine periodically in the beginning, they were much lighter but came with worse cramps... about 6-9 months i stopped having it all together but would experience light light spotting a day or two here and there. now, after being period free for like a year it came back for a week and now i've been spotting for a week after that. i've talked to my doctor about it and she says basically the whole environment is changed and it's very different for everyone. i definitely wouldn't worry so long as you are feeling ok, and just always have something on hand in case it does decide to show up. and, if you ever have concerns i'm sure your doctor won't mind a call... i'm sure many people with IUD's have a ton of questions and concerns during the first year or even longer.