Is Adenomyosis A Type Of Endometriosis and Fibroids: What to Know

September 13, 2025

Is Adenomyosis A Type Of Endometriosis and Fibroids: What to Know

Pelvic pain and heavy periods have many causes, and three conditions often come up in the same conversation: adenomyosis, endometriosis, and uterine fibroids. They can coexist and share symptoms, but they are not the same disease. Understanding how they differ—and where they overlap—can help you get to the right diagnosis and treatment faster.

Adenomyosis vs. Endometriosis vs. Fibroids: What’s the Difference?

Adenomyosis

Adenomyosis occurs when the tissue that normally lines the inside of the uterus (endometrial glands and stroma) grows into the muscular wall of the uterus (myometrium). This can make the uterus enlarged and tender and often causes heavy, painful periods and cramping. The exact cause is unknown; risk factors may include prior uterine surgery (such as cesarean delivery), childbirth, and being in your 30s–50s. Prevalence estimates vary because diagnosis can be challenging.

Endometriosis

Endometriosis is when tissue similar to the uterine lining grows outside the uterus—on the ovaries, fallopian tubes, pelvic peritoneum, and sometimes beyond. It’s associated with inflammation, scarring, and adhesions. Common symptoms include chronic pelvic pain, painful periods, pain with sex, bowel or bladder pain during menstruation, and infertility. About 1 in 10 people of reproductive age are affected.

Uterine Fibroids

Fibroids (leiomyomas) are benign smooth muscle tumors of the uterus. They are very common by age 50 and can range from pea-sized to very large. Symptoms depend on size and location and can include heavy or prolonged bleeding, pelvic pressure, urinary frequency, constipation, and reproductive challenges, especially if fibroids distort the uterine cavity.

Are They Related?

Short answer: no, adenomyosis is not a type of endometriosis or fibroids, but these conditions can coexist. Adenomyosis and endometriosis both involve endometrium-like tissue in places it does not belong, but adenomyosis is within the uterine muscle, while endometriosis is outside the uterus. Fibroids are structurally different (muscle tumors), yet they can cause similar bleeding and pressure symptoms. It’s not uncommon for someone to have more than one of these conditions at the same time, which can blur the clinical picture.

Typical Symptoms and When to Suspect Each

Adenomyosis: heavy menstrual bleeding, severe cramping, a diffusely enlarged, tender uterus, pain with intercourse. Symptoms may worsen with age until menopause.
Endometriosis: pelvic pain that can be cyclical or constant, severe period pain out of proportion to findings, pain with sex, bowel movements, or urination during periods, infertility.
Fibroids: heavy or prolonged periods, clotting, pelvic pressure or fullness, back pain, urinary frequency, constipation; fertility or pregnancy complications if fibroids distort the uterine cavity.

Red flags warranting evaluation include soaking pads hourly, anemia symptoms (fatigue, shortness of breath), severe pain interfering with daily life, pain with bowel or bladder function, or difficulty getting pregnant.

How They’re Diagnosed

History and pelvic exam: may reveal an enlarged, tender (adenomyosis) or irregular, bulky (fibroids) uterus. Endometriosis may have subtle exam findings or tender nodules.
Imaging:
- Transvaginal ultrasound (TVUS): first-line for fibroids; can show signs suggestive of adenomyosis (asymmetric thickening, myometrial cysts, “heterogeneous” muscle). Ovarian endometriomas (chocolate cysts) are often visible.
- MRI: helpful when ultrasound is inconclusive, to map fibroids, and to characterize adenomyosis more precisely.
Diagnostic laparoscopy: sometimes used to confirm and treat endometriosis; allows direct visualization and biopsy.
Pathology: adenomyosis can be definitively confirmed under a microscope, typically after hysterectomy; otherwise, diagnosis is clinical/imaging-based.

Treatment Options

Management depends on your symptoms, fertility goals, severity, and coexisting conditions. Many options are uterus-sparing.

Adenomyosis

Non-surgical: NSAIDs for pain; hormonal therapies to reduce bleeding and pain (combined oral contraceptives, progestins, the levonorgestrel-releasing intrauterine device/LNG-IUD). The LNG-IUD is FDA-approved for heavy menstrual bleeding and is often effective for adenomyosis-related bleeding and pain.
Advanced hormonal therapy: GnRH agonists or antagonists may be used short term to suppress symptoms.
Procedures: uterine artery embolization (UAE/UFE) can reduce bleeding and pain in many; focal adenomyomectomy is an option in select cases; definitive treatment is hysterectomy if childbearing is complete and symptoms are severe.

Endometriosis

Non-surgical: NSAIDs; hormonal suppression with combined oral contraceptives, progestins, the LNG-IUD, or GnRH analogs. FDA-approved oral GnRH antagonists (e.g., elagolix; relugolix combination therapy) can reduce moderate-to-severe pain in appropriate candidates.
Surgical: laparoscopic excision or ablation of endometriosis lesions; surgery can improve pain and may improve fertility in selected patients.
Fertility care: if conception is a priority, options include timed intercourse after treatment, ovarian stimulation with intrauterine insemination, or IVF depending on disease severity and age.

Fibroids

Non-surgical: NSAIDs; tranexamic acid (an antifibrinolytic) for heavy bleeding; hormonal therapies including combined pills, progestins, and the LNG-IUD. FDA-approved oral GnRH antagonist combination therapies (elagolix or relugolix combinations) can reduce heavy menstrual bleeding associated with fibroids.
Procedures: uterine fibroid embolization (UFE), radiofrequency ablation, focused ultrasound (in select centers).
Surgery: myomectomy (fibroid removal) preserves the uterus and may help fertility, especially for cavity-distorting fibroids; hysterectomy is definitive for those who are done with childbearing.

Note: The “best” option is individualized. Discuss medication side effects, bone health considerations with GnRH analogs, and the impact of each procedure on future pregnancy.

Fertility and Pregnancy Considerations

Adenomyosis may be associated with subfertility, implantation failure, and miscarriage in some studies. Hormonal suppression or targeted surgery may be considered on a case-by-case basis.
Endometriosis can affect egg quality, tubal function, and pelvic anatomy. Early evaluation is reasonable if pregnancy does not occur after 6–12 months (sooner if age ≥35 or severe pain).
Fibroids—especially submucosal or large intramural fibroids that distort the cavity—can impair fertility and increase miscarriage risk; myomectomy can improve outcomes in selected cases.

When to See a Specialist

Seek care if you have heavy bleeding, severe pain, anemia, difficulty getting pregnant, or inadequate relief on current therapy. A gynecologist with expertise in minimally invasive surgery, reproductive endocrinology, or interventional radiology (for UFE) may be helpful, depending on your priorities.

Key Takeaways

Adenomyosis is not a type of endometriosis or fibroids—each is distinct—but they can coexist and share symptoms.
Ultrasound and MRI help differentiate conditions, but endometriosis may require laparoscopy for confirmation.
Effective, uterus-sparing treatments exist for all three conditions; plans should align with symptom relief and fertility goals.
Trusted guidance from evidence-based sources and a personalized care plan can meaningfully improve quality of life.

This article is for general education and does not replace personalized medical advice. Speak with your clinician about your specific situation.

References and Trusted Resources

MedlinePlus (NIH): Endometriosis — https://medlineplus.gov/endometriosis.html
MedlinePlus (NIH): Uterine Fibroids — https://medlineplus.gov/uterinefibroids.html
MedlinePlus (NIH): Adenomyosis — https://medlineplus.gov/adenomyosis.html
ACOG Patient FAQs: Endometriosis — https://www.acog.org/womens-health/faqs/endometriosis
ACOG Patient FAQs: Uterine Fibroids — https://www.acog.org/womens-health/faqs/uterine-fibroids
ACOG Patient FAQs: Adenomyosis — https://www.acog.org/womens-health/faqs/adenomyosis
NICHD (NIH): Endometriosis — https://www.nichd.nih.gov/health/topics/endometriosis
NICHD (NIH): Uterine Fibroids — https://www.nichd.nih.gov/health/topics/uterine-fibroids
FDA: Drug information on approved therapies (e.g., elagolix, relugolix combination, tranexamic acid) — https://www.fda.gov/drugs/drug-safety-and-availability