I had the Mirena IUD for eighteen months. The lumbar area of my back loosened significantly and I could feel the bones moving around similar to when you are in the fairly advanced stages of pregnancy. I actually injured my back several times and pretty badly as I was trying to exercise as if my hormone levels were normal. i had to stop taking yoga because even though I had practiced for years, my back couldn't tolerate it. Prior to this, I had never had any back injuries. Not one. I had the IUD taken out three weeks ago. I lost a size in the first two weeks. My back is still a mess from the injuries and I am just hoping it will tighten back up and heal over time. GET THE THING OUT! The side effects are real and it is not just your imagination. I can't believe I put up with it as long as I did. Looking back I just couldn't grasp that an IUD could cause so many physical problems...but it did.