Summary:
Mirena is a long acting intrauterine hormone-releasing
(LNG-IUS) contraceptive system with a flexible plastic
T-shaped frame bearing a levonorgestrel(LNG)-
containing cylinder which releases small doses
levonorgestrel into the uterine cavity after insertion with
maximum effect on the endometrium and minimum
progestogenic side-effect. LNG causes thinning of the
endometrium, atrophy of the endometrial glands and
decidualisation of the endometrial stroma. The most
common side-effect of LNG-IUS is unscheduled vaginal
bleeding in the first 3 months, so proper counseling is
needed. In some cases functional ovarian cysts may occur
which are relatively small, symptomless and resolved
spontaneously within a short time.