Levonorgestrel, Pharmacokinetics, Efficacy and Safety 45years of exposure to a contraceptive method) was 0.1[55]. The LNG-IUD, in
particular, is the most effective IUD available as reported in a number of
studies with a global cumulative pregnancy rate of <0.5% [56].
The LNG-IUD is also an effective contraceptive option for women to
select immediately post-abortion. One study followed 305 women who
received the Mirena® IUS immediately post-abortion for up to five years.
There was a total of two pregnancies for a pregnancy rate of 0.8% at five
years. There was a discontinuation rate due to expulsion of 7.1% at one year
and 10.5% at five years [57] which is higher than the interval expulsion rate of
2%–3% per year [58]. An LNG-IUD is therefore safe to insert immediately
after either spontaneous or induced abortions. An LNG IUD can also be easily
inserted after childbirth, but the expulsion rate is higher compared with
interval insertion.
The LNG-releasing IUD has a significant role in the medical management
of gynecological conditions. The Mirena® LNG-IUD can be effective in
treating a variety of gynecological disorders including menorrhagia,
dysmenorrhea, pain associated with endometriosis and endometrial
hyperplasia. It can also be used as an alternative to hysterectomy for women
with bleeding problems as well as an adjunct to estrogen replacement therapy.
Heavy Menstrual Bleeding
The LNG-releasing IUD (LNG - IUD) has been found to be more
effective than oral hormonal treatment for heavy menstrual bleeding. LNG-
IUD has been reported to result in a reduction in menstrual blood flow of
86%–97% [59]. One study comparing the LNG-IUD and norethisterone
showed that the LNG-IUD reduced menstrual blood flow by 94%, while with
norethisterone the reduction in menstrual blood loss was 87% [60]. After three
cycles of treatment, 76% of the LNG-IUD group wished to continue the
treatment, compared with only 22% of the medical therapy group [60]. In a
Cochrane review which included 21 RCT studies with LNG-IUD, there was a
greater reduction in menstrual blood loss, improvement in the quality of life
and an overall acceptance of the IUD for longer time durations. The only
drawback in comparison to oral therapy was that it was associated with more
minor adverse effects than oral therapy [61]. In comparison to hysterectomy,
adverse effects such as bleeding and spotting are more likely to occur with
LNG-IUD, but LNG-IUD provides a better alternative to surgery in most
cases. There is no conclusive evidence of a difference in satisfaction rates
between surgery and LNG-IUD [62].