I've had the mirena (levonorgestrel) for a little more than 2 years and start having brown discharge. i haven't had a period since being pregnant 2 years ago.

Not uncommon: Even though the mirena (levonorgestrel) will thin your uterine lining and even stop periods for many women, it is not uncommon to have some vaginal discharge/spotting on the rare occasion. As long as you're not having any itching/odor/pain then you should be fine but feel free to consult if you have other questions/concerns. Get STD testing if with a new partner.