You know, now that you mention the feeling of a "baby kicking" in your side, I have had that same experience. I even went to the doc to find out if I had a hernia or what could be the cause. Strange!! I would never have associated the movement to the mirena until now. I have now come to the only logical explanation for this strange movement, and it might be that the hormones in the mirena can cause spastic colon symptoms. This is where the large intestine, or colon, will twitch on and off. It is a strange feeling.