If you were my patient, I would provide you the following information first:
Chapter 7 in Contraceptive Technology Intrauterine Devices (IUDs)
By David A.Grimes, MD
The approved life span of the levonorgestrel system is 5 years, although the protection with the system in place may last at least 7 years. While contraceptive effectiveness is discussed in more detail in Chapter 27, a simple formula explains why today’s IUDs provide superior contraception (Figure 7-2). The effectiveness in the community of any contraceptive is related to a number of factors. These include the inherent ability of the method to prevent pregnancy (efficacy) and the user’s compliance (adherence to the regimen, such as pill taking) and continuation (ongoing use over time). Factors impairing effectiveness include a woman’s fecundability (reflecting age, body mass index, prior salpingitis, etc.) and frequency of coitus. Although combined oral contraceptives have excellent efficacy, compliance is only fair—as is continuation. Hence, the contraceptive effectiveness of combined oral contraceptives falls in the middle tier. In contrast, IUDs have excellent efficacy and users exhibit high compliance and high continuation rates (about 85% to 90% at one year). This translates into superior protection against unintended pregnancy.
Both of the intrauterine contraceptives in the United States rank in the top tier of contraceptive effectiveness (along with surgical sterilization, implants, and injectable contraceptives). In combined World Health Organization and Population Council trials, the first-year discontinuation rate of the TCu 380A for accidental pregnancy was only 0.7 per 100 women, and even lower rates occurred in years two through ten. In World Health Organization trials, the cumulative 12-year failure rate with the TCu 380A was 2.2 pregnancies per 100 women. In three trials conducted by Leiras, the Finnish manufacturer of the levonorgestrel system, the first-year cumulative failure rate was 0.14 per 100 women, and the cumulative five-year failure rate was only 0.71 per 100 women. In the Population Council’s randomized trial of the levonorgestrel intrauterine system vs. the TCu 380A, the seven-year cumulative failure rates were 1.1 and 1.4 per 100 women, respectively. In contrast, the overall ten-year failure rate with all methods of tubal sterilization in the United States is 1.9 per 100 women. Thus, contemporary intrauterine contraceptives rival the effectiveness of tubal sterilization.
One of the most intriguing aspects of intrauterine contraception is the evolving story of cancer prophylaxis. Seven case-control studies around the world have examined the potential association between non-medicated or copper IUD use and development of endometrial cancer. Six of the seven found protection against endometrial cancer from devices, and the effect was statistically significant in two (including the Cancer and Steroid Hormone Study of the Centers for Disease Control and Prevention). The only study not to find benefit related to a steel ring used in China, which is not relevant to Western practice. While the mechanism of action is unknown, it may relate to the altered endometrium associated with intrauterine contraception. Similarly, progestin-releasing intrauterine contraceptives should also protect against this cancer, as is true of contraceptives that deliver a progestin systemically. Indeed, the levonorgestrel device has been used to treat endometrial hyperplasia and adenocarcinoma. Two studies have addressed cervical cancer, and both found a 40% reduction in risk associated with IUDs, which was not statistically significant.
Medical Benefits of the Levonorgestrel Intrauterine System
Topical delivery of progestin to the uterine cavity has exciting therapeutic uses aside from contraception. Some are well-established and approved indications overseas, while others are still being explored. Although average menstrual blood loss increases among users of the TCu 380A, the opposite occurs among users of the levonorgestrel system. Overall blood loss drops about 90%, and 20% or more women stop bleeding altogether. This translates into clinically important increases in hemoglobin and iron stores. Some evidence supports a benefit in treating heavy bleeding associated with adenomyosis and leiomyomas.
Indeed, the levonorgestrel system can be used to treat heavy menses, not just prevent them. Trials have compared this approach to medical treatments with an oral progestin, a nonsteroidal anti-inflammatory drug, or tranexamic acid (not available in the United States). The levonorgestrel system proved superior to the other alternatives. In addition, this system has been found an acceptable (and inexpensive) alternative to endometrial ablation or hysterectomy.
Another logical use of the levonorgestrel intrauterine system is as part of hormone replacement therapy in menopause. Many women suffer from unpleasant side effects of oral progestins given along with estrogen. In addition, nuisance bleeding is the primary reason women abandon hormone replacement therapy. Use of the levonorgestrel system leads to profound suppression of the endometrium, which then ceases to bleed. Lack of uterine bleeding during hormone replacement therapy is desirable for the woman and her clinician.
This answer came almost entirely from the 19th edition of Contraceptive Technology, a book that describes how all the contraceptives work, the advantages and disadvantages of each and much more! The chapters are by nationally recognized experts.
Click here to see how to order this important reference book and other important books for clinicians, counselors and women and men wanting the latest contraceptive information.
On the basis of these benefits, my suggestion would be to leave your Mirena in place for 2 to 5 more years (until age 49 to 52), IF THAT IS WHAT YOU WANT TO DO.
So you can show all this to your doctor or nurse practitioner and you must let me know what you decide to do
Now, December 10th, please tell us what you have decided to do.
Key Words: Mirena IUD, 5 years, menopause, Contraceptive Technology, Dr. David Grimes, Intrauterine Devices, levonorgestrel system, effectiveness, cancer protection, medical benefits, heavy menses, hormone replacement therapy
Reference: Grimes DA. Intrauterine devices (IUDs) IN Hatcher RA, Trussell J, Nelson AL. et al. Contraceptive Technology 19th edition, pages 119-122: Ardent Media Inc. 2008
Posted 11-12-2009, Updated 11-14-2009, Updated 12-10-2009