Levonorgestrel
"I got the Mirena two months ago. It hurt a little when the doctor put it in, and I cramped for about a day afterwards. I had no discomfort after that until I got my period a month later. My period was 2 1/2 weeks long (which has never happened in my life) with weird discharge and a lot of cramping. The main issue I've had with the Mirena is a lot of cramping and brown slimy discharge. I'm hoping it gets better, my Doc says to give it some time."