I've been on mirena for about a year and a half now. After the first three months following the insertion I haven't had a single period or spotting at all. About a day ago, I noticed some lighter brown discharge which then proceeded to turn into a very dark brown color. It doesn't have a foul odor and I'm not experiencing any pain, just some mild gas, which is consistent with the types of periods I had before I got mirena. I had a UTI and yeast infection a couple weeks ago that were treated successfully, and at that visit also had an STD test which came back negative. I guess my question is whether or not I should be concerned, if the stress of the UTI/yeast infection caused some change, or if this is just very "old" blood from periods that I haven't had in a year. I suppose I should mention that this started a few days after some not-so-gentle sex (first time after the UTI and yeast infection). Again, no pain and not an excessive amount of discharge. Help!