HOLY H...
I am due to have one done in 3 weeks... And at our clinic they said the error rate on the insertion (as in over-insertion) is like, 1 in every 500. The nurse said there was a doctor there that had it happen a year ago, and the lady got sick, and she sued, and now the doctor is not practising at all anymore because her insurance premiums went through the roof!

Oh dear. I am seriously having doubts now. I'm just a scaredy-cat sometimes though...???