Hi, I just had my 2nd Mirena put in two days ago, so I am speaking from my VERY recent experience. Also, I have not heard about uterus perforation. I received mine after my 3rd child 12 weeks postparum.
Big hint...take 2 Motrin 1/2 hour before your appointment, I wasnt advised to do anything special before this appointment and the 1st question my Dr. asked when she walked in the room was did you take any Motrin?
So here's the honest deal(from my experiences) my 1st Mirena was put in 5 years ago, I can't remember if they told me to take Motrin before that appointment but it barely bothered me going in at all and absolutely no cramping. I could'nt understand what the big deal was.
My second Mirena (2 days ago) surprised me because it did hurt quite a bit while being inserted for about 30 seconds, not enough to put me into tears but it really did hurt and I did cramp up during and after the procedure. As soon as I left the office I headed straight for the nearest drug store for Motrin to help the cramping. 20 minutes later I felt totally fine.
I have to say that even with the pain that I experienced I would go through the procedure every 6 months if that was the protocal. It is SOOOO worth it, beyond the birth control benefit having no periods, PMS, and no worry's about missing a pill! I think that it is the greatest thing going.
I say go for it...oh yeah, and take your Mortin a 1/2 hour before your appontment. :-D