If you’ve experienced years of debilitating, painful periods but haven’t yet received a diagnosis, you’re not alone. It takes an average of seven to nine years from the start of symptoms to receive a diagnosis of conditions like endometriosis and adenomyosis. These complex conditions are poorly understood, even by doctors.

Endometriosis and adenomyosis are two distinct yet similar conditions. Both diseases involve abnormalities in the endometrium, the tissue lining the uterus. In endometriosis, tissue resembling the endometrium grows outside the uterus, causing inflammation, implants, and adhesions on organs and surfaces of the pelvic cavity. In adenomyosis, endometrial tissue remains in the uterus (womb) but grows into its muscular walls and forms small pockets.

This article explains the differences and similarities between endometriosis and adenomyosis and discusses management options for these conditions.

Who Gets These Conditions, and Which Is More Common?

Adenomyosis occurs inside the uterus, whereas endometriosis develops outside it. Endometriosis often affects people of childbearing age and is more commonly diagnosed in those who have not given birth. Adenomyosis, on the other hand, typically develops in people in their 40s who’ve had children. It can also develop at younger ages but go undiagnosed.

It’s hard to know just how many people are affected by endometriosis and adenomyosis, because the conditions often go undiagnosed. A 2023 study in the journal Biomolecules estimated that 11.4 percent of women had endometriosis, with new diagnoses peaking between ages 30 and 34 years.

Adenomyosis rates are harder to determine since diagnoses are often based on tissue examination after a hysterectomy. Many studies have reported that in the United States, adenomyosis is present in a wide range (for example, 9 percent to 62 percent) of people undergoing hysterectomy, with diagnosis peaking between ages 40 and 50. Newer imaging studies such as ultrasound and MRI can help identify adenomyosis earlier.

Symptoms of Adenomyosis and Endometriosis

Endometriosis and adenomyosis can share many symptoms, including:

• Intensely painful menstrual periods
• Pelvic pain during sexual intercourse
• Abdominal bloating or a feeling of heaviness
• Irregular menstrual bleeding

However, certain symptoms are more associated with each condition. Adenomyosis tends to cause very heavy menstrual periods and an enlarged uterus. Endometriosis is more likely to cause bladder and bowel symptoms, such as diarrhea, constipation, bloating, and pain with bowel movements. Symptoms of endometriosis may also include unusually short or long periods or spotting between cycles.

Symptoms of either condition can range from mild to severe, and many people may not know they have endometriosis or adenomyosis for many years.

Fertility Challenges

Infertility is one of the biggest concerns among people with endometriosis. One member of MyEndometriosisTeam asked, “What if I can’t have children? Did anyone have children without infertility treatments? How long did it take you to even get pregnant?”

Many people discover they have endometriosis when they experience difficulty conceiving. An estimated 25 percent to 50 percent of infertility cases also involve endometriosis.

Adenomyosis may be linked with challenges such as miscarriage, preterm birth, and infants who are small for their gestational age. However, because adenomyosis is more likely to occur later in life, it is less commonly a cause of infertility.

Causes of Adenomyosis vs. Endometriosis

There’s not just one cause of endometriosis or adenomyosis. Many risk factors are thought to contribute to these conditions.

Adenomyosis occurs when the endometrium grows inside the myometrium (muscle wall), causing the entire uterus to get bigger. A combination of hormones, genetics, inflammation, and trauma can lead to adenomyosis. Risk factors include age over 40, childbirth history, and previous uterine surgeries, such as cesarean section or fibroid removal. Having endometriosis may also increase the likelihood of developing adenomyosis.

Some researchers believe that endometriosis may result from retrograde menstruation — when menstrual blood flows back into the pelvic cavity through the fallopian tubes instead of exiting through the cervix. Risk factors for endometriosis include genetics and immune system problems. If a family member has endometriosis, you may be at higher risk developing it.

It isn’t uncommon to have both adenomyosis and endometriosis, although there’s not enough research to say that having one condition makes you more likely to develop the other. However, similar cell types and hormones are involved in both conditions.

Diagnosis of Adenomyosis vs. Endometriosis

The diagnosis of either condition starts with a visit to a gynecologist. They’ll ask about your medical history and may do a physical exam, including a pelvic exam to check your uterus.

A doctor might suspect you have adenomyosis if a pelvic exam shows that your uterus feels larger, softer, and more tender than usual. Imaging tests, like ultrasound or MRI, can help confirm adenomyosis. Your doctor may also recommend a biopsy, which involves taking a small sample of endometrial tissue to be examined at a laboratory. The biopsy can help rule out other diseases that may cause heavy menstrual bleeding.

Endometriosis is harder to detect through routine exams. A pelvic exam might reveal only some pain and tenderness. The most accurate way to diagnose endometriosis is with laparoscopy, a minimally invasive procedure that allows doctors to observe endometriosis lesions directly and, if necessary, remove tissue for testing. Laparoscopy can help confirm the diagnosis, relieve symptoms, and temporarily improve fertility.

Treatment Options for Adenomyosis vs. Endometriosis

Treatment for endometriosis depends on your symptoms and your plans for future pregnancy. Medications to treat endometriosis often include nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin). Hormonal therapies can help manage symptoms by suppressing the menstrual cycle and relieving pain associated with periods. Medication options include:

• Hormonal birth control, including birth control pills, injections, a patch or vaginal ring, an implant, or certain IUDs
• Gonadotropin-releasing hormone (GnRH) antagonists or agonists, such as elagolix (Orilissa) and leuprorelin acetate (Lupron)
• Danazol (Danocrine), a medication that changes hormone levels

Endometriosis may require surgery to relieve pain and improve fertility. Laparoscopic surgery to remove the endometrial tissue is sometimes recommended, especially for those who want to improve fertility. Hysterectomy, or removal of the uterus, may be recommended for people who have severe symptoms and don’t plan to become pregnant. It’s important to note that endometriosis symptoms may or may not improve with hysterectomy.

Adenomyosis symptoms also may improve with hormonal treatment. NSAIDs can help ease pain and inflammation, and fibrinolysis inhibitors, such as tranexamic acid (Lysteda) may improve menstrual bleeding. When family planning is complete, adenomyosis can be cured by hysterectomy.

In both conditions, symptoms typically disappear after menopause, when the menstrual cycle stops completely.

Talk to Others Who Understand

MyEndometriosisTeam is the social network for people with endometriosis and their loved ones. On MyEndometriosisTeam, more than 136,000 members come together to ask questions, give advice, and share their stories with others who understand life with endometriosis.

Has your doctor considered a diagnosis of endometriosis or adenomyosis? When did you finally get a diagnosis? Share your experience in the comments below, or start a conversation by posting on your Activities page.