I've had a Mirena IUD twice. I got it the first time in January 2003 after the birth of my now 2.5 year old. The only side effects I had was spotting for about six weeks and then, gradually over time, my periods became less and less and by August I had virtually no monthly bleeding. I loved it! I had no complaints whatsoever.
In Nov. 2003, I got the crazy idea to have another child.
So I had the Mirena removed and my cycles returned in Dec. and I was pregnant by February.
I got my second Mirena in January 2005. This time, I had spotting for quite a bit longer, about 3 months, but then it stopped. I still have not had a period but I'm bf my 7 month old. I have no side effects from the Mirena; I absolutely love it.
You mentioned you are considering having it removed. Are you experiencing unpleasant side effects? You didn't mention any ....