I had no bother with it being put in, loved it for a whole year, had no periods, no migraines (which were linked to ovulation with me) and ne PMT. A couple of months of feeling funny, went for my check and it had slipped down into my cervix and I had got pregnant!
This is VERY VERY rare, but my advice would be, if you think there might be something wrong with your coil (if you can feel it, or, like me, I started to feel all hormonal again - this was with mirena) then get it checked before it is too late!