given that [the pregnancy test] was negative and you mentioned increasingly light flows over time my best guess is that this is a "normal" mirena side effect. simply stated if the uterine lining is like grass or lawn estrogen is like the fertilizer (causes a thickening of the lining) and progesterone is like the lawnmower (keeps the lining thin by three different mechanisms). this is why depoprovera (high dose synthetic progesterone) brings about a thin lining and why birth control pills (relatively progesterone dominant) bring about shorter lighter periods. the mirena distributes significant amounts of synthetic progesterone right at the level of the lining of the uterus. that is why a large percent of mirena users lose their periods after 12 months of use. as mentioned this can also happen with birth control pills and the depo provera shot. a thin lining is a healthy lining when it is caused by hormones in birth control methods. your lining will regrow after the mirena is removed---or even toward the end of the five years as the level of hormone in the iud is tapering down. .
i've been on mirena for a year. my period has suddenly stopped after several months of lighter flow. is this normal?