"i&#039;ve had my mirena for a year and 8 months. i&#039;m a 40 yr old with 2 children. yes it is very effective for birth control, but i have had unexpected weight gain of 40-50 pounds! i am so depressed because of it, because the only difference in my life is the mirena. i also wake up with low back pain occasionally, and i did have spotting for several months the first year pretty much every week for many months. i cannot explain this weight gain, i am ready for removal. also i have developed bacterial vaginosis at least once from the mirena. and i was not sexually active at the time and i&#039;m in a monogomus relationship, so yeah..it sucks..."