Continuation rates and satisfaction with the Levonorgestrel Intrauterine System. Letter to the Editor in response to an article published in volume 31, by Dr. Ewies

We are writing in response to the paper published in Gynecological Endocrinology (31:1–6, 2009) by Dr. Ewies. This publication claims that the LNG-IUS has high rates of sexual dissatisfaction, high rates of discontinuation, high rates of progestagenic side effects, and high tissue and serum levels of LNG.

In claiming that there is ‘overwhelming evidence’ of ‘high discontinuation and dissatisfaction rates amongst (LNG-IUS) users’ Dr. Ewies cites studies on the use of the LNG-IUS for the treatment of heavy menstrual bleeding (HMB) and endometriosis.

We would like to clarify that the LNG-IUS is not licensed for use in endometriosis.

Dr. Ewies does not cite other studies that have shown higher continuation rates in the treatment of HMB [1–4 ]. We suggest that it would have been appropriate to compare the continuation rates of the LNG-IUS with a comparator treatment. For example, a recent systematic review and meta analysis of randomised controlled trials demonstrated that the failure rates of endometrial ablation or resection and LNG-IUS are similar up to 2 years follow up [5].

In addition, we believe that the reasons for the discontinuation over a 5-year period are important, particularly in contraception trials, and may include desire for pregnancy or other personal reasons rather than dissatisfaction. We suggest therefore, that a comparison of discontinuation rates versus other methods intended for up to 5 years of use would have been more relevant for the reader.

Dr. Ewies surmises that the Finnish study which showed very high continuation rates on the use of LNG-IUS for contraception ‘could be biased because more than 70% of women in this survey used LNG-IUS because of dissatisfaction with previous methods of contraception’. We propose that this group would actually be harder to satisfy, and thus could have led to lower continuation rates.

We would also like to comment that there are also studies with other 20 μg releasing intrauterine devices which show high continuation rates [6].

Dr. Ewies claims there are ‘high rates of progestogenic adverse effects leading to discontinuation before the 5 years’. We also draw attention to the rates observed in clinical trials: Luukkainen et al. [7] found gross cumulative discontinuation rate of 2.7% at 1 year, and a rate of 12% at 5 years [8] due to progestogenic adverse effects. We question the comparison of discontinuation rates due to progestagenic adverse effects of the LNG-IUS and copper IUD and propose that a more valid comparison would be between the LNG-IUS and other progestogens-containing contraceptives.

In addition, counselling prior to insertion of an intrauterine contraceptive is important to subsequent satisfaction of the use [9] and we suggest perhaps that the high discontinuation rate in the series reported by Ewies could be due to lack of information provided to the user.

The presentation of the pharmacokinetic data is not based on direct comparisons between the LNG-IUS and POP tissue and serum concentrations, but is speculation based on results from several separate non-comparative trials dating mainly to the 1980s. Arguments based on data from a study that looked at an oral HRT preparation containing 50 μg ethinyl estradiol on the effect of HRT on serum LNG levels [10] are flawed since such preparations are not currently marketed for HRT.

We would also like to point out that there are errors contained with Table 1 including incorrect values and the inclusion of data from developmental products which have never been marketed (Nilsson et al. [11] refers to a developmental product with a release rate of 50 μg/day, not the marketed LNG IUS and Ratsula et al. [12] refers to an intracervical device).

Dr. Ewies states that ‘prolonged oestrogen deprivation will have a profound negative effect on a woman's sex drive’; however, this is not based on clinical data. In addition, he is critical of clinical studies showing a positive effect of LNG-IUS on sexual functioning. We draw attention to the study conducted on over 2000 women by Witting et al. [13] which concluded that use of the LNG-IUS was associated with more desire, arousal, and satisfaction, and with less pain, whereas there was no significant association between the LNG-IUS and orgasm and lubrication.

We would also like to address the misinterpretation of the study published by Halmesmäki et al. [14]. The main conclusion of the study was that amongst women with menorrhagia, there was no change in sexual satisfaction or sexual problems by the LNG-IUS. Indeed, Halmesmäki writes ‘results may not be clinically as important because the changes in the scores were relatively small’.

In conclusion, we welcome reviews and scientific debate on the LNG-IUS; however, we believe that these should represent a systematic and objective analysis of the available data.