The IUS (Mirena® coil) contains a small amount of a progestogen hormone which is released gradually. It can be a very useful device during the perimenopause as it has three potential uses - as a contraceptive, a treatment for heavy periods (half of women stop having periods with it) and it provides the progestogen component of HRT. If being used for the latter, it needs changing after 5 years.
Taken from "My Menopause Doctor" website