Safety and Efficacy of the Levonorgestrel-releasing Intrauterine System

Recent Insights

Kristina Gemzell-Danielsson; Pirjo Inki; Oskari Heikinheimo


Expert Rev of Obstet Gynecol. 2013;8(3):235-247. 

In This Article

Five-year View

As presented above, there is an increasing number of nulliparous women requiring effective contraception for longer. The development of a new IUS targeted for younger women has recently been initiated. A very recent publication focuses on the low-dose LNG contraceptive system (LCS) – a new LNG-releasing IUS developed for contraception. Two experimental IUSs with different LNG release rates (LCS 12 and LCS 16 with corresponding in vitro LNG release rates of 12 and 16 µg/day, respectively) that can be used for up to 3 years were compared with the currently marketed 20 µg LNG-IUS (Mirena). A potential advantage of a smaller IUS with a smaller insertion tube diameter may be easier and less painful placement, therefore, improving its acceptability and use in women with no previous vaginal delivery. In addition, IUSs with lower daily release rates of LNG lead to lower serum hormone levels, and may potentially reduce associated progestin-related adverse effects.[98]

Another group, which is growing in numbers, is obese women. These women are not good candidates for estrogen-containing contraceptives, and the efficacy of systemically acting progestin-only contraceptives may be impaired. Frequently, obesity is associated with dysfunctional uterine bleeding, which may be worsened by use of a Cu-IUD. The limited evidence published to date suggests that the efficacy and safety profile of the LNG-IUS in obese women are similar to that observed in women with normal BMI. More research would be welcome in this group of women.

Recent studies have indicated that uptake of LARCs can be increased by proper counseling.[73] In the future, owing to their superior effectiveness in real-life use, cost–effectiveness and established safety profile, the LARCs are expected to become the contraceptive methods of first choice to women throughout their reproductive period.