Does Endometriosis Cause Inflammation and Fibroids: What to Know

September 13, 2025

Does Endometriosis Cause Inflammation and Fibroids: What to Know

Short answer: Endometriosis is an inflammatory condition, but it does not cause uterine fibroids. The two are distinct disorders that can occur together, share some risk factors, and sometimes worsen each other’s symptoms. Understanding how they differ—and where they overlap—can help you get the right diagnosis and treatment.

Endometriosis vs. Fibroids: What Are They?

Endometriosis

Endometriosis occurs when tissue similar to the uterine lining grows outside the uterus—commonly on the ovaries, fallopian tubes, or pelvic peritoneum. This tissue responds to hormones, bleeds or becomes inflamed during cycles, and can lead to scarring and adhesions. It’s a chronic, estrogen-dependent, inflammatory disease associated with pelvic pain, painful periods, pain with sex, and sometimes infertility. Estimates suggest it affects about 1 in 10 people of reproductive age assigned female at birth (NIH/NICHD; ACOG).

Uterine Fibroids

Uterine fibroids (leiomyomas) are benign smooth muscle tumors that develop in or on the uterus. They are also estrogen- and progesterone-responsive. Many people have no symptoms; others experience heavy menstrual bleeding, pelvic pressure, frequent urination, constipation, painful periods, or fertility and pregnancy issues. Fibroids are very common—by age 50, most people assigned female at birth will have them, though not all will be symptomatic (NIH/NICHD; ACOG).

Do Endometriosis and Fibroids Cause Each Other?

No. Current evidence does not show that endometriosis causes fibroids, or that fibroids cause endometriosis. They are separate diseases with different origins: endometriosis involves endometrium-like tissue outside the uterus and an inflammatory immune response; fibroids are clonal growths of uterine muscle cells with increased extracellular matrix. However, both are influenced by ovarian hormones, particularly estrogen, and both can coexist in the same person. When they do, symptoms may be more complex and require a tailored treatment plan (ACOG; HHS Office on Women’s Health).

How Inflammation Fits In

Endometriosis is inflammatory by nature. Lesions trigger local immune activation, with elevated inflammatory cytokines and nerve growth factors in the pelvis. This inflammation contributes to pain, scarring, and sometimes bowel or bladder symptoms (NIH/NICHD).
Fibroids and inflammation: Fibroids themselves are not primarily inflammatory, but research shows they are associated with changes in extracellular matrix and signaling pathways that can include low-grade inflammation. Large or multiple fibroids can cause local uterine inflammation and heavy bleeding, which may lead to anemia and fatigue (NIH/NICHD; ACOG).

Bottom line: endometriosis clearly causes inflammation; fibroids can be associated with local inflammatory changes and symptoms, but are not considered an inflammatory disease in the same way.

Shared Risk Factors—and Key Differences

Shared: Higher lifetime exposure to estrogen (e.g., early menarche), family history, and certain genetic factors are linked to both conditions. Both are most common during the reproductive years (ACOG).
Differences: Fibroids are especially common among Black individuals and with increasing age up to menopause; obesity is a known risk factor. Endometriosis often presents with severe pain out of proportion to exam findings and can occur even in adolescents and people with normal BMI (NIH; ACOG).

Symptoms: Where They Overlap and Diverge

Shared symptoms: Pelvic pain, painful periods, pain with sex, and fertility challenges can occur in both.
More typical of fibroids: Heavy or prolonged menstrual bleeding, bulk symptoms (pelvic pressure, bloating, frequent urination), and anemia.
More typical of endometriosis: Cyclical pelvic pain, bowel or bladder pain during periods, pain that starts early in menstrual life, and pain that persists despite standard period medications.

Getting the Right Diagnosis

A careful history and pelvic exam guide initial evaluation. Your clinician may use:

Pelvic ultrasound: First-line imaging for fibroids; can also detect ovarian endometriomas.
MRI: Helpful when ultrasound is inconclusive, for surgical planning, or when both conditions are suspected.
Laparoscopy: The gold standard for diagnosing endometriosis is direct visualization and, when possible, biopsy. Many clinicians, however, start treatment based on symptoms and imaging to avoid surgical delays (ACOG).

Treatment Options When Endometriosis, Fibroids, or Both Are Present

Treatment is individualized, balancing symptom relief, side effects, future fertility, and preferences. Options include:

Medications

NSAIDs: Reduce menstrual pain and inflammation (more effective for endometriosis-related pain).
Hormonal therapies: Combined estrogen-progestin pills/patch/ring or progestin-only options (including levonorgestrel IUD) can lighten bleeding and reduce pain for both conditions.
GnRH agonists/antagonists with add-back therapy: Temporarily lower estrogen to shrink fibroids and relieve endometriosis pain. The FDA has approved oral GnRH antagonists with add-back therapy for heavy menstrual bleeding due to fibroids (FDA). These are typically used for limited durations and require monitoring.
Tranexamic acid: Non-hormonal option to reduce heavy menstrual bleeding, often used for fibroid-related HMB (ACOG).

Procedures

Laparoscopic excision/ablation of endometriosis: Can improve pain and fertility in selected patients (ACOG).
Myomectomy: Surgical removal of fibroids, preserving the uterus; appropriate when fertility is desired.
Uterine artery embolization (UAE/UFE): Minimally invasive procedure that shrinks fibroids by blocking their blood supply; not typically used when future pregnancy is the primary goal.
Hysterectomy: Definitive treatment for fibroids when childbearing is complete. This does not treat endometriosis outside the uterus, so additional treatment may be needed if both are present.
MR-guided focused ultrasound: A nonincisional option for selected fibroid cases (availability varies).

If you have both conditions, your care team may stage treatments (for example, manage heavy bleeding first to correct anemia, then address chronic pain), or combine surgical approaches in one procedure depending on findings and goals.

Can Lifestyle Help With Inflammation?

Lifestyle changes cannot cure endometriosis or fibroids, but they may help control symptoms and overall inflammation:

Regular physical activity and weight management
Balanced diet emphasizing fiber, fruits/vegetables, and limiting alcohol
Prioritizing sleep and stress reduction
Smoking cessation

Discuss supplements or diets with your clinician; evidence is evolving and some products may interact with medications.

When to Seek Care

See a clinician if you have any of the following:

Heavy bleeding (soaking a pad/tampon every 1–2 hours, passing large clots)
Severe pelvic pain, especially if it disrupts daily activities
Symptoms of anemia (fatigue, dizziness, shortness of breath)
Pain with sex, bowel movements, or urination
Difficulty getting pregnant after 6–12 months of trying

A gynecologist, and when needed a multidisciplinary team (radiology, fertility specialists, pain management), can help tailor a plan.

Key Takeaways

Endometriosis is an inflammatory, estrogen-dependent condition; fibroids are benign uterine tumors influenced by hormones.
Neither condition is known to cause the other, but they can coexist and complicate symptoms.
Accurate diagnosis and individualized treatment—often combining medication and procedures—provide the best outcomes.

This article is informational and not a substitute for personalized medical advice. Consult your healthcare professional for diagnosis and treatment options right for you.