"i recently had my second mirena inserted. i had my first one for 6 years. i had a little bit of spotting for the last year or so, perhaps due to the hormones reducing.  i had gained almost 60 pounds since my first insertion. but it was gradual and i never attributed it to the mirena. i recently went on a low carb diet...started exercising and voila, 40lbs lost in a 3 month period! i guess it wasn&#039;t the mirena after all. when i got my second one inserted i gained 5 lbs of water overnight and bloated something fierce.  i began to worry, what if i start to gain again? well i gave it 2 weeks i&#039;m down on the scale lower than ever! i&#039;m a happy mirena user."