I had my Mirena IUD inserted in August of 2005, 3 months after birth of daughter. After 21 months of satisfaction, an abdominal pain woke me up one morning. Maybe it was a rupturing ovarian cyst. I took about 8 pepto bismol pills, nearly developed an impaction a few days later and for the next 2.5 months have had constipation despite fibercon, prune juice use. I think it is weird that it took so long to develop these side-affects. It makes sense that that it is a side-effect since progesterone slows down peristalsis. I haven't seen many others complain of this.