Dr. Heikinheimo: A marked reduction in uterine bleeding is a hallmark of LNG-IUS use. The typical bleeding pattern during its use is oligomenorrhea or amenorrhea, with minor occasional bleeding.
OBG Management: What data do we have on the effect of the LNG-IUS on heavy menstrual bleeding?
Dr. Heikinheimo: This effect was explored in a randomized, open-label, active-control, parallel-group trial of 79 women who used the LNG-IUS and 81 women who were given medroxyprogesterone acetate (MPA) over six menstrual cycles.4 When the trial began, all of these women experienced menstrual blood loss of 80 mL or more. By trial’s end, the LNG-IUS had caused a significantly greater reduction in menstrual blood loss than MPA had, and more women using the LNG-IUS had successful treatment. Success was defined as menstrual blood loss below 80 mL and a reduction in menstrual blood loss of 50% or more from baseline.
Women who had organic or systemic conditions that may cause heavy uterine bleeding were excluded, except for women who had small fibroids that did not exceed 5 mL in volume.
OBG Management: What is the mechanism of action for the LNG-IUS in the reduction of heavy menstrual bleeding?
Dr. Heikinheimo: The high local concentration of levonorgestrel causes marked suppression of the endometrium. This suppression is associated with several biochemical events, such as reduced expression of steroid receptors, altered expression of steroid-metabolizing enzymes, and inhibition of insulin-like growth factor activity.12 These alterations render the endometrium insensitive to growth-promoting entities, such as estradiol. The result is thin endometrium and uterine bleeding that is either minor or nonexistent.
How does the LNG-IUS compare with endometrial ablation
and hysterectomy?
OBG Management: How does the LNG-IUS compare with endometrial ablation and hysterectomy in the treatment of heavy menstrual bleeding?
Dr. Heikinheimo: The LNG-IUS is increasingly used in the treatment of heavy menstrual bleeding. In the Finnish VUOKKO study, women who were referred to a gynecologic outpatient clinic because of heavy menstrual bleeding were randomized to hysterectomy or to treatment with the LNG-IUS. At 5 years, approximately half of the women randomized to the LNG-IUS were still using the device.5 Also, quality of life and psychological well-being were similar between the groups. Although 40% of the women randomized to the LNG-IUS eventually underwent hysterectomy, the cost of the treatment was significantly lower in the LNG-IUS group than in the hysterectomy group ($2,820 versus $4,660).5
Endometrial resection is less commonly used to treat heavy menstrual bleeding in Scandinavia. However, in research studies, the efficacy of the LNG-IUS has been comparable to that of endometrial resection.3
Is the LNG-IUS completely benign?
OBG Management: What adverse reactions are associated with the LNG-IUS?
Dr. Heikinheimo: The main effect is an altered bleeding pattern. The device can cause spotting and irregular bleeding, oligomenorrhea, amenorrhea, or even heavy bleeding. Most of these changes occur during the first 3 to 6 months after insertion. Altered bleeding is seen in approximately 30% of women using the LNG-IUS. Proper patient information, provided before and at insertion, is the key element in guiding these women through these initial inconveniences.13 After the first months, the number of bleeding and spotting days commonly decreases, although bleeding may remain irregular. Amenorrhea develops in about 20% of users by the end of the first year of use.9
In most women who experience heavy menstrual bleeding, the number of bleeding and spotting days may increase during the first months of therapy but declines with continued use, as does the volume of blood loss each month.
A potential concern with irregular bleeding is that it may mask the signs and symptoms of endometrial polyps or malignancy. For this reason, abnormal uterine bleeding should be evaluated before insertion of the LNG-IUS. Similarly, any woman who develops unexplained bleeding during prolonged use of the device should also be evaluated.
Does the LNG-IUS raise the risk of breast cancer?
OBG Management: Because the LNG-IUS is hormonal contraception, some women may worry about their risk of breast cancer when using it. What do we know about that risk?
Dr. Heikinheimo: A large post-marketing study in Finland revealed that the risk of breast cancer among users of the LNG-IUS is similar to that among the general population.14 The results are clear: When used for contraception, the LNG-IUS is not associated with an increased risk of breast cancer.
Is patient satisfaction high?
OBG Management: Here’s a critical question—are women happy with the LNG-IUS?
Dr. Heikinheimo: They certainly appear to be. Continuation rates in large post-marketing trials have been high, in the range of 65% at 5 years.13 I often tell my patients and students that, as a gynecologist, I see lots of happy women; many of them are using the LNG-IUS. That means that many women are likely to use more than one LNG-IUS during their fertile years.