Adenomyosis and endometriosis are both disorders of the endometrial tissue that lines the inside of the uterus. But they develop differently and have some different symptoms.

In adenomyosis, endometrial cells grow within the muscles of the uterus. These misplaced cells follow the menstrual cycle, bleeding monthly. The uterus wall thickens and may cause pain and heavy bleeding. It usually affects older people, and it’s recently been associated with infertility.

In endometriosis, the endometrial-like cells grow outside the uterus. The tissue is commonly found on the ovaries, supporting ligaments of the uterus, and in the cavities of the pelvis. There they follow the menstrual cycle, bleeding monthly.

This may cause pain and may affect fertility. It usually occurs with adolescents and people of reproductive age.

You can have one or both of these disorders. A 2017 study of 300 women diagnosed with adenomyosis between 2008 and 2016 found that 42.3 percent also had endometriosis.

Adenomyosis and endometriosis are both fairly common. Less is known about the prevalence of adenomyosis because it hasn’t been studied as extensively. It’s also more difficult to diagnose.

Endometriosis is estimated to affect about 10 percent of women of child-bearing age.

The estimated prevalence of adenomyosis ranges widely.

A 2012 study of 985 women at one gynecology clinic found that 20.9 percent had adenomyosis. But the study noted that this was a self-selected population that came to the clinic because they had symptoms.

Symptoms of adenomyosis and endometriosis, including pain, range from mild to severe.

But some people with endometriosis have no symptoms. About one-third of women who have adenomyosis have no symptoms.

Some symptoms can mimic those caused by other conditions, such as ovarian cysts or uterine fibroids.

Typical symptoms are as follows:

Adenomyosis

Endometriosis

  • painful periods (dysmenorrhea)
  • painful sexual intercourse (dyspareunia)
  • painful bowel movements (dyschezia)
  • painful urination (dysuria)
  • pelvic pain
  • fatigue, nausea, and diarrhea, especially during your period

The exact causes of adenomyosis and endometriosis aren’t known. But researchers have identified likely mechanisms and risk factors. Theories include the following:

  • Adenomyosis and endometriosis may result from tissue injury and repair (TIAR) after trauma to the uterus. Estrogen production is involved in this process.
  • Stem cells might be activated by injury to endometrial tissue. They can then grow outside of their usual location in adenomyosis and endometriosis.
  • Menstrual blood that goes astray through the fallopian tubes (retrograde menstruation) may leave endometrial tissue in the pelvis or other areas.
  • Genetic factors may be involved. Endometriosis tends to run in families.
  • Immune system problems may cause a failure to find and regulate straying endometrial tissue in both adenomyosis and endometriosis.
  • Problems with the body’s hormone system and estrogen may transform embryonic cells in your abdomen into endometrial cells.
  • Your lymph system may carry endometrial cells to other areas.

Some suggested explanations combine two or more of these theories.

Researchers have identified some risk factors associated with adenomyosis and endometriosis.

More studies are needed because some results are inconsistent.

Adenomyosis

Higher risk for adenomyosis is associated with:

  • having had more than one child
  • being treated with tamoxifen for breast cancer
  • having had surgery of the uterus, such as dilation and curettage
  • depression and higher use of antidepressants

Studies of an adenomyosis association with smoking and ectopic pregnancy have mixed results.

Endometriosis

Higher risk for endometriosis is associated with:

  • earlier onset of menstruation
  • shorter menstrual cycle (less than the typical 28-day cycle)
  • heavy menstrual bleeding
  • obstruction of menstrual flow
  • taller height
  • higher alcohol and caffeine consumption
  • a blood relative with endometriosis (this increases your risk sevenfold)
  • late menopause

Decreased risk for endometriosis is associated with:

If you don’t have symptoms, your first diagnosis may occur when your doctor is treating you for another problem.

If you have symptoms, such as pelvic pain, your doctor will take your medical history and ask you about your symptoms:

  • When did they start?
  • How long do they last?
  • How do you rate your pain?

The doctor will examine you physically and likely order imaging tests.

To rule out other possible causes of pelvic pain, your doctor may order a urine test, pregnancy test, Pap test, or vaginal swabs.

Adenomyosis

Adenomyosis is difficult to diagnose. In the past, it was diagnosed only by examining tissue samples, for example after uterine surgery.

Adenomyosis causes the uterus to become enlarged, so your doctor will perform a physical exam to feel whether your uterus is swollen or tender.

In some cases where a more precise image is required, sonohysterography may be used. This involves an injection of saline solution into the uterine cavity before a sonogram.

Endometriosis

Your doctor will take your medical history. They’ll also ask about others in your family who may have had endometriosis.

Your doctor will examine your pelvic area to feel for cysts or other abnormalities. They’ll likely order imaging tests, including a sonogram and possibly an MRI.

The sonogram may be done with a wand type of scanner across your abdomen or inserted into your vagina.

Your doctor may also use laparoscopic surgery to look for endometrial tissue outside of the uterus. If a diagnosis isn’t clear, a tissue sample can be taken during surgery to confirm the diagnosis or to be examined under the microscope.

Research is ongoing into noninvasive ways to diagnose endometriosis using blood tests. But so far, no accurate biomarker (indicator that you have the condition) has been found.

Treatment for both conditions ranges from minimal (over-the-counter medications) to more invasive (hysterectomy).

Treatment options in between these extremes vary. This is because of the differences in where the misplaced endometrial tissue is located.

Discuss your treatment options with your doctor. Some of the questions to consider are:

  • Do you want to have children?
  • Is your pain intermittent, just around your periods?
  • Does chronic pain prevent you from carrying out your daily activities?
  • Are you near menopause, when adenomyosis related symptoms may go away?

Adenomyosis

If your symptoms are mild, your doctor may recommend using over-the-counter anti-inflammatory drugs just before and during your period. For more severe symptom management, there are other options.

Hormones are used to help control increased estrogen levels that contribute to symptoms. These include:

  • oral contraceptive pills
  • high-dose progestins
  • a levonorgestrel-releasing intrauterine device
  • danazol
  • gonadotropin-releasing hormone (GnRH) agonists and antagonists, like elagolix
  • endometrial ablation, which is an outpatient procedure that uses a laser or other ablation techniques to destroy the lining of the uterus
  • excisional procedures, which use laparoscopy to cut out the affected adenomyosis areas of the uterus (this has been only 50 percent successful, because it doesn’t get all of the adenomyosis)
  • uterine artery embolization, which is a minimally invasive procedure with moderately good reported results
  • MRI-guided focused ultrasound surgery (MRgFUS), which is a noninvasive procedure using focused ultrasound energy that’s delivered to deep tissue without damaging the surrounding tissue (this successfully reduced adenomyosis symptoms, according to a 2016 review)
  • hysterectomy, a complete removal of the uterus, which eliminates adenomyosis (it’s not appropriate for people who want to have children)

Endometriosis

For mild symptoms, over-the-counter anti-inflammatory drugs may help. For more severe symptoms, there are other options.

Anti-inflammatory drugs may be combined with hormonal treatments. Hormone supplements may help:

  • regulate your periods
  • reduce endometrial tissue growth
  • relieve pain

These can be prescribed in a staged fashion, starting with a low dose of oral contraceptives and seeing how you respond.

The first line of treatment is usually low-dose combined oral contraceptive pills. Examples include ethyl estradiol and progestins.

A second-tier of treatment includes progestins, androgens (danazol), and GnRH. These have been shown to reduce endometriosis pain. The progestins may be taken orally, injected, or as an intrauterine device.

The hormonal contraceptive treatments may stop your periods and relieve symptoms as long as you’re taking them. When you stop taking them, your periods will return.

If you want to get pregnant, there’s evidence that taking and then stopping hormonal treatments may improve chances of fertility with in vitro fertilization.

Conservative surgery can remove endometriosis laparoscopically while keeping your uterus intact. This may relieve symptoms, but the endometriosis can return.

Laparoscopy can also be used with heat, current, or laser treatments to remove the endometriosis.

Hysterectomy (removal of the uterus) and possible removal of your ovaries is considered a last resort.

Both adenomyosis and endometriosis can be painful over time. Both are progressive disorders, but they’re treatable and not life threatening. Early diagnosis and treatment can lead to a better outcome for pain and symptom relief.

Menopause usually relieves adenomyosis symptoms. Some people with endometriosis may still have symptoms after menopause, though this isn’t very common.

Both adenomyosis and endometriosis may make it harder to get pregnant. If you want to get pregnant, talk with your doctor about the best treatment plan for you.

New methods of conservative surgery may be able to relieve pain and symptoms while preserving your uterus and ovaries.

The good news is that there are many ongoing studies on adenomyosis and endometriosis. We likely find out more about what causes these disorders in the future, and new therapies will continue to be develop.