Quick definitions

• Adenomyosis: Endometrial tissue (the lining of the uterus) grows into the uterine muscle (myometrium). This can cause a uniformly enlarged, tender uterus, heavy menstrual bleeding, and painful periods.
• Uterine fibroids (leiomyomas): Noncancerous tumors made of muscle and fibrous tissue that grow in or on the uterus. They vary in size and number and can cause heavy bleeding, pelvic pressure, pain, and fertility or pregnancy issues depending on location.

Importantly, adenomyosis and fibroids can occur together, and either can exist without symptoms.

Symptoms and who is at risk

Shared symptoms

• Heavy or prolonged menstrual bleeding (sometimes with clots)
• Pelvic pain, cramping, or low back pain (often worse around menstruation)
• Enlarged uterus and pelvic pressure or fullness
• Pain with intercourse
• Fatigue from iron-deficiency anemia due to blood loss

Risk factors

• Adenomyosis: More common in people in their 30s–50s, those who have given birth, and those with prior uterine surgery. Hormonal factors (estrogen) are thought to play a role.
• Fibroids: Can occur at any reproductive age; risk rises with age until menopause. Family history and race/ethnicity matter—Black women develop fibroids more often and at younger ages. Hormonal factors and obesity are also linked.

How adenomyosis and fibroids are diagnosed

Diagnosis starts with a detailed history (bleeding pattern, pain, fertility goals), a pelvic exam, and lab work to check for anemia. Imaging is critical to distinguish between conditions and to plan treatment.

Pelvic exam

• Adenomyosis: Uterus may feel uniformly enlarged and tender.
• Fibroids: Uterus may feel irregular, nodular, or asymmetrically enlarged, depending on fibroid number and location.

Ultrasound (first-line)

Transvaginal ultrasound is typically the first imaging test. It is widely available, radiation-free, and can often identify fibroids and suggest adenomyosis.

• Findings suggestive of adenomyosis: Diffuse thickening of the junctional zone, asymmetrical thickening of the uterine walls, small cysts within the muscle, and a “streaky” or heterogeneous appearance.
• Findings suggestive of fibroids: Distinct, well-circumscribed masses that may be within the uterine wall (intramural), bulging into the cavity (submucosal), or projecting outward (subserosal). Some fibroids calcify.

MRI (problem-solving and surgical planning)

Pelvic MRI offers higher soft-tissue detail and is especially helpful when ultrasound is inconclusive, when adenomyosis and fibroids co-exist, or when precise mapping is needed before surgery. MRI is more accurate for characterizing adenomyosis (for example, thickening of the junctional zone) and for defining fibroid number, size, and location.

Definitive diagnosis

Historically, adenomyosis could only be definitively diagnosed by microscopic examination after hysterectomy. Today, characteristic ultrasound/MRI findings are usually sufficient for clinical diagnosis when paired with symptoms. Fibroids are typically confirmed by imaging and, rarely, by pathology if removed.

Treatment options: what to know

Treatment is tailored to your symptoms, health history, and fertility goals. Many options focus on controlling bleeding and pain; others shrink or remove tissue. Not every option is appropriate for every person.

Non-surgical (medical) options

• NSAIDs (e.g., ibuprofen) for pain and cramping.
• Hormonal therapies, which can reduce bleeding and pain:
  • Combined oral contraceptives or progestin-only pills.
  • Levonorgestrel-releasing IUD, which can be particularly effective for heavy bleeding and dysmenorrhea, including in adenomyosis when the uterine cavity allows placement.
  • GnRH analogs/antagonists (medicines that lower estrogen) can shrink fibroids and reduce bleeding. FDA-approved oral combination therapies include elagolix/estradiol/norethindrone (brand example: Oriahnn) and relugolix/estradiol/norethindrone (brand example: Myfembree) for heavy menstrual bleeding due to fibroids in premenopausal women. These medications carry warnings about bone mineral density loss and require monitoring; they are used for limited durations and may not be suitable for everyone.
• Iron supplementation if iron-deficiency anemia is present.

Minimally invasive procedures

• Uterine artery embolization (UAE): Interventional radiology procedure that blocks blood flow to fibroids, shrinking them and reducing bleeding and pressure. Some patients with adenomyosis also experience symptom relief.
• Hysteroscopic resection: Removal of submucosal fibroids via the vagina and cervix; preserves the uterus and can improve bleeding and fertility in select cases.
• Radiofrequency ablation of fibroids (laparoscopic or transcervical) uses targeted heat to shrink fibroids and reduce symptoms.
• MR-guided focused ultrasound: An incisionless technique that thermally ablates selected fibroids under MRI guidance; availability varies.

Surgical options

• Myomectomy (removal of fibroids) via hysteroscopic, laparoscopic, or open approach. This is a common choice for people desiring future fertility.
• Adenomyomectomy (surgical excision of focal adenomyosis) may be considered in select cases but is technically complex; outcomes depend on disease extent and surgeon expertise.
• Hysterectomy (removal of the uterus) is definitive for both adenomyosis and fibroids when childbearing is complete and other treatments have not worked or are not appropriate.

Note: Endometrial ablation can reduce heavy bleeding but is generally not advised for those who wish to preserve fertility and may be less effective when adenomyosis is significant.

Fertility and pregnancy considerations

• Fibroids can affect fertility and pregnancy, especially if they distort the uterine cavity (submucosal) or are large. Myomectomy can improve outcomes in selected situations.
• Adenomyosis has been associated with subfertility and miscarriage in some studies, likely due to changes in uterine muscle and inflammation. Treatments that quiet the lining or reduce inflammation may help symptoms; reproductive specialists can tailor care.
• Always discuss fertility goals before any procedure, as some treatments can affect pregnancy safety or the ability to conceive.

When to see a clinician

• Bleeding that soaks through pads or tampons hourly for several hours
• Periods lasting more than 7 days, or significant bleeding between periods
• Pelvic pain that interferes with daily activities
• Signs of anemia (fatigue, dizziness, shortness of breath)
• Difficulty getting pregnant or recurrent pregnancy loss

Bring a symptom diary (bleeding days, pain scores, medications taken) to your visit. Clarify your goals—symptom control, uterine preservation, or fertility—so your care team can align a plan to your priorities.

Key takeaways

• Adenomyosis and fibroids can cause similar symptoms but differ in location and treatment approach.
• Transvaginal ultrasound is the usual first test; MRI helps when the diagnosis is unclear or for surgical planning.
• Treatment ranges from medications and IUDs to minimally invasive procedures and surgery—tailored to symptoms and fertility goals.
• Seek evaluation for heavy bleeding, significant pain, anemia, or fertility concerns.

Trusted sources and further reading

• NIH MedlinePlus: Adenomyosis; Uterine Fibroids
• NICHD (NIH): Uterine Fibroids Overview; Adenomyosis (overview)
• FDA safety/approvals: FDA approval for therapy to manage heavy menstrual bleeding due to fibroids; Myfembree safety information

This article is educational and not a substitute for personalized medical advice. If you suspect adenomyosis or fibroids, consult a clinician who can evaluate your symptoms and imaging and help choose the safest, most effective options for you.