abnormal uterine bleeding
"I have two children and I decided to get the Mirena IUD.  I got it placed a little over two weeks ago. The insertion was not painful at all, just a mild pressure, and I only experienced faint cramps for the rest of the day.  Unfortunately I have had ongoing menstrual bleeding ever since (16 days now).  There are no cramps and no other side effects, but constantly having to carry around tampons is annoying.  I was on the pill for over ten years before I had my kids, and I never had periods, so this is especially annoying."