Adenomyosis is a common disease of the uterus, yet little is understood about the causes and risk factors, diagnosis is difficult, and there are few effective treatments besides hysterectomy. Adenomyosis can exist on its own, or in conjunction with other pelvic diseases such as endometriosis. The incidence of adenomyosis in the general population is not known, because estimates of incidence have only been done in populations of women undergoing hysterectomy.
Symptoms of adenomyosis may include:
- Painful periods
- Painful ovulation
- Chronic pelvic pain (all month long)
- Heavy and/or prolonged menstrual bleeding
- Large blood clots
- Pain in the thighs
Adenomyosis can sometimes be asymptomatic, and it is not known why some women can get debilitating pain and extremely heavy bleeding from adenomyosis, while others have no symptoms at all.
The medical definition of adenomyosis is when glandular tissue, normally only found in the endometrium ( the inner lining of the uterus), is found in the myometrium (the muscle wall of the uterus). Adenomyosis used to be commonly called endometriosis interna, or endometriosis of the uterus, because of the similarity to endometriosis, which occurs when tissue similar to the endometrium is found in the pelvis or elsewhere in the body.
The cause of adenomyosis is not known. There are some studies that associate c-sections, prior uterine surgeries, and/or miscarriages with a risk of adenomyosis, although other studies have found no associations. One theory is that invasion of cells from the surface endometrium into the deeper muscular layers of the uterus can result in adenomyosis. In addition, developmental origins have been proposed, where tissue laid down in the wrong place during formation of the embryo can result in adenomyosis later in life. This theory may be the most likely to be true, as there is some support for this theory in the development of endometriosis, and endometriosis and adenomyosis often occur together.
Diagnosis of adenomyosis is difficult, because there are no tests that can definitively confirm or rule out a diagnosis. In some cases, adenomyosis can be suspected from ultrasound results or MRI results, but normal ultrasound or MRI results do not rule out the presence of adenomyosis. Adenomyosis can also be suspected from pelvic exams, when the uterus is large or tender. Since the main symptoms of pelvic pain and heavy bleeding can result from many other causes, it is difficult to diagnose adenomyosis based on symptoms. Other conditions causing similar symptoms include endometriosis, fibroids, and hormonal imbalances.
Sometimes adenomyosis symptoms can be managed with medication. Pain relievers such as NSAIDs can be used to treat pain, and in some cases hormonal medications such as the birth control pill or a Mirena IUD can treat the symptoms by stopping periods. Medications to control heavy bleeding are often not used by gynecologists, but they can be effective and prevent the need for a hysterectomy if heavy bleeding is the only symptom. The most effective medication for heavy bleeding is Lysteda (tranexamic acid), but DDAVP (desmopressin) can also be used.
Endometrial ablation is sometimes a suggested treatment for the heavy bleeding caused by adenomyosis, but it can make adenomyosis pain worse. In addition, adenomyosis may confer a greater likelihood of endometrial ablation failure. Doctors will often say that “the ultimate cure” for adenomyosis is a hysterectomy. Although hysterectomy is obviously effective at curing uterine pain and heavy menstrual bleeding, it is a major surgery and sometimes has unwanted effects and complications . If we understood the causes of adenomyosis better, we might be able to develop more specific treatments for the underlying cause or causes, and avoid such extreme surgery.
It is commonly stated on medical websites that adenomyosis goes away after menopause. However, it was often said that endometriosis goes away after menopause, and now it is known that for at least some women, maybe most, it does not. We don’t really know the incidence of endometriosis post-menopause because women who complain of pelvic pain after menopause are usually told that the pain cannot be endometriosis, and are not investigated for endometriosis, even if they have a previous history of it. It may be a similar fallacy to believe that adenomyosis goes away after menopause.
It is also often said that adenomyosis is more common in women over 35. The idea that it is more common in older women may come from the fact that it can only definitively be diagnosed by pathology studies post-hysterectomy. Older women with pelvic pain and/or heavy menstrual bleeding may be more willing to have a hysterectomy to solve the problem than younger women, who may want to keep their uterus for child-bearing. Therefore, adenomyosis ends up getting diagnosed more often in the older age group, but may be just as common in younger women. In fact, adenomyosis is starting to be diagnosed more often in younger women, using better imaging techniques.
There are many unanswered questions about adenomyosis and more research is needed in many areas of this disease. Better methods for diagnosis would be extremely helpful, as at the moment adenomyosis can only be confirmed by hysterectomy. Answers about why some women have such severe symptoms while others have none, what causes adenomyosis in the first place, whether it really can persist after menopause, and more, may help lead to less invasive and more effective treatments for this disease.