Mirena may also affect heavy periods in other ways
In some women with heavy bleeding, the total blood loss per cycle progressively decreases with continued use. The number of spotting and bleeding days may initially increase but then typically decrease in the months that follow. Bleeding may also continue to be irregular. Call your healthcare provider if bleeding becomes heavy after it has been light for a while. About 20% of women may have no period at all at the end of one year of use with Mirena.