Elsevier

Contraception

Volume 65, Issue 2, February 2002, Pages 129-132
Contraception

Original research article
Bleeding patterns and clinical performance of the levonorgestrel-releasing intrauterine system (Mirena) up to two years1 ,

https://doi.org/10.1016/S0010-7824(01)00302-XGet rights and content

Abstract

The objectives of this study were to evaluate the bleeding patterns and clinical performance during the first 2 years of use of an intrauterine system releasing 20 μg/day of levonorgestrel (LNG-IUS, Mirena). Two-hundred-fifty-six women accepted use of Mirena from April 1998 through September 1998. The gross cumulative discontinuation rate due to pregnancy and expulsion were significantly higher in women who used the device because of heavy bleeding. There was one pregnancy at the 15th month of use after an inadvertent expulsion of the device. The continuation rate was 66.2 at the end of the second year. Forty-four percent of women reported amenorrhea at the 6th month of use. This rate maintained stability at 50% after 12 and 24 months of use. Spotting was present in 25% of the users at 6 months, decreasing to 8% and 11% at 18 and 24 months, respectively. Oligomenorrhea was described by one-quarter of women and was similar at each observation period. Removals due to menstrual bleeding problems were concentrated in the first 6 months of use and mostly due to amenorrhea or menorrhagia. In conclusion, LNG-IUS showed a high contraceptive efficacy and a good continuation rate up to 2 years. In addition, a reduction of blood loss was observed a few months after insertion.

Introduction

The levonorgestrel-releasing intrauterine system (LNG-IUS, Mirena) is a contraceptive method registered in Europe, Latin American, U.S., and Canada. The effectiveness was tested up to 7 years in different settings, and the cumulative pregnancy rate was from 0.0 to 0.5 up to 7 years of use [1], [2], [3].

One of the main characteristics of the LNG-IUS is to cause a reduction in the amount of blood loss during each menstrual period. Due to this characteristic, it has been used as a medical treatment for women with menorrhagia [4]. However, the reduction of blood loss is the principal cause of discontinuation among women using the device for contraception [1].

The menstrual pattern of LNG-IUS users varies depending on the population studied. However, these differences could be, in part, resulting from the women’s interpretation, the service providers’ opinion regarding bleeding pattern, or the system of evaluation. The knowledge of bleeding pattern may be helpful to counsel potential users of the device and for future clinical indications of the method.

The objectives of this study were to evaluate the bleeding patterns and clinical performance in women using LNG-IUS as a contraceptive method for up to 2 years in Campinas, Brazil.

Section snippets

Materials and methods

This was a prospective trial conducted at the Human Reproduction Unit, Department of Obstetrics and Gynecology, School of Medicine, Universidade Estadual de Campinas (UNICAMP), Campinas, Brazil. The Institutional Review Board approval was obtained from the Ethical Committee of the University. All women voluntarily signed an informed consent.

A total of 256 women aged 18 to 39 years (mean 27.0 ± 0.41), who requested an IUD as a contraceptive method and accepted the LNG-IUS after explanation of

Results

Complete characterization of the cohort has been published elsewhere [3]. In summary, 60% of acceptors were in the 20 to 29 years age bracket, and more than 70% of the women had one or two previous pregnancies. The gross cumulative discontinuation rates by reason and the continuation rate are presented in Table 1. There was one pregnancy at the 15th month of use after an inadvertent expulsion of the device. The expulsion rate was significantly higher in the group that had insertion of the

Discussion

The clinical performance of the LNG-IUS was similar to the findings of other previous studies, confirming that the device is associated with high contraceptive efficacy, low risk of infection, high continuation rate, and significant reduction of menstrual bleeding [1], [2], [3], [7], [8], [9], [10], [11], [12]. The only reason for discontinuation which was significantly higher in the group with heavy menses before insertion of the device was expulsion. This finding was also observed in our

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Financial support for this study was partially provided by Schering of Brasil, São Paulo, Brazil.

1

Mirena is a registered trademark of Leiras Oy, Turku, Finland.

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