Hi Dr. Hatcher,
I have had my Mirena for a little over a year, and last night I went to check my strings and they were not there-after a lot of checking and changing of positions, I called and went into my Midwife's office this morning and they could not see them either. They ordered an ultrasound to check the position of it; however, this isn't able to be done until Tuesday.
I know that my Mirena wasn't expelled, but the PA who checked me said that it may have shifted higher in my uterus. Is this something that commonly occurs? If so, is my IUD still as effective as it was when I could feel the strings? If it has moved, is there any way that it could perforate my uterine lining or migrate outside the uterus?
I also noticed when I was checking my strings, that I was able to feel my cervix pretty easily, where as before; I really had to reach to feel it. Can a woman’s cervix change positions with her cycle? And could this be a reason that I can't feel my strings?
I have read a lot of scary things about this issue, but really trust your information. I am just curious what you have to say about this.
Thank you for your help. Kindest regards,
The uterus changes position slightly and an IUD may shift positions within the uterus. Your Mirena IUD is effective anywhere entirely within the uterus and your second note informs you that yours is within the uterus.
The Mirena remains effective as long as it remains within the uterine cavity.
Was a speculum exam done by the PA?
Later this week, let me know the result of the ultrasound.
Her reply on 9-13: “Hi Dr. Hatcher.”
“The speculum exam was done by the PA. She did a full pelvic exam as well and said everything felt like it was supposed to.”
“I had my ultrasound (transvaginal) and the report stated that the IUD was in the proper position. I fell good about it all, except that I don’t have the “security” of being able to feel the strings. Hopefully all will remain well for 4 more years!!! That was an expensive endeavor to find out that everything is fine…better than worrying about it, I suppose.”
You are so right, an expensive set of exercises to find out that everything was okay, but for now, not to worry and you may be happy to know that your IUD is effective for a full 7 years.
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 women in her clinic.
To learn more about the advantages and disadvantages of the Mirena IUD, go to our website at: www.managingcontraception.com and click on Choices.
Key Words: Mirena IUD, strings, positions, ultrasound, expelled, shifted, uterus, effective, cervix, cycle, uterine cavity, speculum
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 9--13-2010, Updated 10-3-2010, Updated 10-17-2010