The levonorgestrel-releasing Mirena® intrauterine system (IUS) is a very effective form of contraception, with a Pearl Index of less than one (0.2 pregnancies for every 100 women who use this method for a year).
Most women who choose this method stick with it (90% continuation rate after three years).
An extensive consultation given before the fitting is an important factor in the high rates of satisfaction. In general, users’ satisfaction depends primarily on whether they received adequate answers to their questions and whether they were warned of possible side-effects beforehand.
It is important that the effect of the Mirena® on menstruation is explained in the consultation:
- By the end of the first year of use, most women only bleed for 1-2 days per month and almost half no longer have any periods at all. From a medical point of view this is a positive thing, and it’s something that most women welcome. However, many women experience it as a confrontation with their identity as women, and this is something that should be discussed. Some women decide not to have a Mirena® for that reason.
- Some users may experience longer periods or breakthrough bleeding (spotting). This is common in the first three to six months, but usually improves significantly after that. Only very rarely is there a need for treatment for prolonged bleeding, or does an IUS have to be removed because of it.