The menstrual bleeding pattern during use of a levonorgestrel intrauterine system

The levonorgestrel intrauterine system (LNG-IUS, Mirena(R)), which has been shown to release levonorgestrel at a rate of 20 mu g daily for a period of 5 years, has proven to be remarkably effective at reducing the volume and duration of menstrual bleeding in women with normal and with excessively heavy menstruation. The patterns of bleeding during the first year of contraceptive use have been studied in detail recently using computer analysis of prospective menstrual diary cards. Bleeding and spotting are common in the first month after insertion, with a median of 18 days (8 days of bleeding and 10 days of spotting). After 6 months, this nuisance bleeding rapidly decreases to a median of 6 days (only 2 days of bleeding and 4 days of spotting), as does the volume of blood lost per month. Women can expect a 60% reduction in blood loss by 3 months, and more than 75% by 12 months, while, for women with menorrhagia due to ovulatory dysfunctional uterine bleeding, there is likely to be a 70% reduction inflow by 3 months, 90% by 6 months and 95% by 12 months. For most women, whether they are using the LNG-IUS for contraception or treatment of menorrhagia, the dramatic reduction in volume of bleeding is a major benefit.