Dienogest as a Treatment for Adenomyosis

Introduction to Adenomyosis

Adenomyosis is a medical condition characterized by the infiltration of endometrial tissue into the muscular wall of the uterus. Unlike endometriosis, where tissue grows outside the uterus, adenomyosis occurs when the endometrial lining pushes into the uterine muscles. This condition often results in thickened uterine walls, leading to symptoms such as heavy or prolonged menstrual bleeding. Those affected frequently endure significant pain during menstruation and may also experience discomfort during intercourse.

The precise origins of adenomyosis remain unclear, but multiple theories have been proposed, including:

– The presence of extra tissue or stem cells in the uterine wall from birth that proliferate during adulthood.
– Endometrial cells being pushed into the uterine muscle due to surgical procedures, such as cesarean sections or fibroid removals.
– Uterine inflammation post-childbirth, which may disrupt the normal boundaries of uterine cell layers.

Available Treatments for Adenomyosis

While some individuals with adenomyosis may not need medical intervention, those experiencing severe symptoms may be advised to take anti-inflammatory medications like ibuprofen, starting three days before their menstrual cycle. These medications can decrease menstrual blood flow and alleviate cramping.

Given that adenomyosis is linked to estrogen levels, progestin-only oral contraceptives may be prescribed to help manage elevated estrogen levels that exacerbate symptoms. In cases of severe adenomyosis, particularly for women who do not plan to have more children, a hysterectomy may be recommended. Typically, adenomyosis tends to resolve after menopause.

Hormonal Treatments: The Role of Dienogest

A recent study published in *Fertility and Sterility* evaluated the safety and effectiveness of dienogest (DNG), a synthetic progestin utilized in oral contraceptives since 1995, for treating symptomatic adenomyosis.

In this randomized, double-blind, placebo-controlled trial conducted across multiple centers in Tokyo, Japan, 67 women diagnosed with adenomyosis were administered either 2 mg/day of DNG or a placebo for 16 weeks. The study found that nearly all participants in the DNG group experienced some irregular uterine bleeding (97% as opposed to 39% in the placebo group), although the frequency of heavy bleeding days decreased. Furthermore, the women receiving DNG reported significantly lower pain levels compared to those in the control group. Importantly, there was no indication of uterine enlargement or severe anemia in the DNG group.

These findings indicate that DNG may provide a well-tolerated and effective option for women suffering from symptomatic adenomyosis. However, due to the higher risk of severe irregular uterine bleeding associated with DNG, caution is warranted for patients with significant uterine enlargement or severe anemia.

Study Limitations and Future Research

One notable limitation of this study is the absence of laparoscopy to definitively exclude a diagnosis of endometriosis. Nonetheless, experienced gynecologists conducted imaging assessments using transvaginal sonography and MRI, lending confidence to the adenomyosis diagnoses. Additionally, the study’s results were confined to a 16-week treatment duration. Given that adenomyosis does not typically resolve until menopause, further research over longer periods—such as five or ten years—will be essential to assess the long-term efficacy and safety of DNG.

Conclusion

Dienogest presents a promising treatment avenue for individuals experiencing symptomatic adenomyosis. Ongoing research will help clarify its long-term impact and suitability for various patient profiles.

Written by Debra A. Kellen, PhD
Reference: Osuga, Y., Fujimoto-Okabe, H., & Hagino, A. (2017). Evaluation of the efficacy and safety of dienogest in the treatment of painful symptoms in patients with adenomyosis: a randomized, double-blind, multicenter, placebo-controlled study. *Fertility and Sterility*, 108(4), 673-678. https://doi.org/10.1016/j.fertnstert.2017.07.021