Yet many people have never heard of this condition, despite the fact that as many as one in five women suffer from it.
Adenomyosis can cause symptoms including irregular and heavy menstrual bleeding and pelvic pain. The severity of symptoms varies by patient – up to a third of women with adenomyosis may have minimal or no symptoms at all.
The condition can also affect fertility. Women with adenomyosis who do become pregnant have an increased risk of miscarriage, premature birth, preeclampsia, and postpartum bleeding.
So what causes adenomyosis and how is it diagnosed and treated? There’s still a lot we don’t understand about this condition, but here’s a little bit about what we know so far.
What Causes Adenomyosis?
There are two main layers in the uterus. The endometrium is the innermost layer in which embryos implant. If there is no pregnancy, this layer is shed for a period. The myometrium is the muscular layer of the uterus. It expands during pregnancy and is responsible for contractions. In people with adenomyosis, endometrial-like cells are found in the wrong place: the myometrium.
Although a large number of women with adenomyosis also have endometriosis, adenomyosis is a different disease from endometriosis. In endometriosis, endometrial-like cells are also found in the wrong place, but outside the uterus, mainly in the pelvic cavity.
Thanks to research, public engagement, and social media, awareness of endometriosis has increased in recent years. Yet adenomyosis is still relatively unheard of.
Read more: Adenomyosis causes pain, heavy periods and infertility, but you’ve probably never heard of it
Diagnostic options are changing and improving
Adenomyosis is a difficult condition to diagnose. Historically, the presence of endometrial-like cells in the myometrium could only be verified by pathological assessment in which the myometrium is examined under a microscope after a hysterectomy (surgery to remove the uterus).
Diagnoses have increased in recent years due to the development of imaging technologies such as MRI and detailed ultrasound of the pelvis. Although adenomyosis is now commonly diagnosed without the need for a hysterectomy, doctors are still developing a standardized method for non-surgical diagnosis.
As a result, it remains uncertain exactly how many women have adenomyosis. Although we know that about 20% of women who have had a hysterectomy for reasons other than suspected adenomyosis are found to have evidence of the condition on pathological assessment.
Adenomyosis is a complex condition
The type of adenomyosis tissue growth in the myometrium can be focal lesions (affecting part of the uterus) or diffuse (affecting a large area of muscle). Adenomyosis can be further classified depending on the depth of invasion of endometrial-like tissue into the myometrium. Scientists and doctors are still investigating whether the type or depth of lesions is related to symptoms – the severity of symptoms and lesions don’t always match.
We don’t yet understand why some women develop adenomyosis, although there is some evidence that it becomes more common with age.
The area between the endometrium and myometrium is believed to become damaged either through the natural processes of the menstrual cycle, pregnancy and childbirth, or through medical procedures. In some women, the damage to the endometrial tissue layer does not heal as it should and the endometrial-like cells invade and grow abnormally in the myometrium. These disrupt the normal functions of the myometrium, leading to pain and bleeding.
It is possible that several mechanisms may contribute and that there is not one common disease-causing factor behind adenomyosis.
How is adenomyosis treated?
Treatment strategies include hormonal medications such as oral contraceptives, progesterone-containing pills, inserting a progesterone-releasing coil (for example, Mirena), or a drug called GnRHa that stops the natural production of sex hormones. Non-hormonal treatments include tranexamic acid. These treatments aim to minimize menstrual bleeding. Pain is often treated with nonsteroidal anti-inflammatory drugs.
Treatments that work for some women don’t for others, lending weight to the argument that there is more than one type of adenomyosis. Treatment strategies should be tailored to the patient, depending on their fertility wishes and symptoms.
If medical treatments do not adequately relieve symptoms, there are surgical options, namely removal of the focal lesions or a hysterectomy.
Read more: Endometriosis: three reasons why care still hasn’t improved
What lies ahead?
Although adenomyosis is a common condition affecting many women, including women of childbearing age, it does not receive enough clinical and research attention. There is also a lack of knowledge and awareness around adenomyosis among many health care professionals and the public. This needs to change so we can improve our understanding of the condition, diagnosis and treatment options.
Scientists and doctors specializing in adenomyosis are still searching for an accurate, non-invasive diagnostic method and, hopefully, a cure one day.