I will never recomend mirena for anyone especially just to control periods. I hated it and I stuck it out for a year. I had it put in 6-8 weeks after my daughter was born and during those 6-8 weeks I felt great and happy. but after getting mirena put in I had one period and then they completely stopped. I gained back all the weight i had lost after birth and ended up with back pain and was tired all the time. I lucked out my daughter has slept through the night from day one. I had to wake her up to feed her during the day so i wasn't tired from a constanst crier.
I had cramps around the time of when i should have had my period. my moodswings were horrible to the point that ppl told me i was nicer when i was pregnant. I eventually got to the point that everytime my daughter cried I couldn't take it and would yell at her to shutup. thats not like me normally. eating habits changed and there are a lot of sideaffects that they do not let you know about.
sorry this is so long but each person is different. while i had no period my best friend would bleed for nearly a month every time she has her period. since she already was bipolar it has made those issues worse.
if you have ever had issues with ovarian cysts it will make those worse and it is possible for it to fall out or poke through your uterus. I have been dealing with depression ever since having mirena put in and since i've had it taken out i've been off ever since. but each person does react differently to different hormones and drugs. although if your sensitive to hormones then be prepared for trouble.