Hi M.,
I've had the Mirena in since my son was 8 wks, he's now 16 months. I absolutely love it! I gained weight after I had my son, I think, because I was eating so much - I was hungry ALL THE TIME while breastfeeding. Only recently have I begun to drop the pounds, 26 pounds so far. It came off rather easily when I started getting serious with the exercise and really watching my food intake. "They" say that Mirena is not supposed to cause weight gain because of the low dose of hormones, but every woman is differnt! Have there been any changes in your routine? A decrease in activity levels or maybe not eating as well as you used to? I had my thyroid checked like the other mom suggested and it came back normal, but you might want to look into it. Also I hate to say it, but even if nothing has changed in your life or routine, our bodies are always changing as we age. At a certain point we just aren't able to do the things we use to and get the same results. That realization is what made me start getting serious about my own health.
I hope you find something that works for you! God bless you and your family!
J.