Does Endometriosis Flare Up During Period and Fibroids: What to Know

If your pelvic pain reliably spikes around your period, you’re not imagining it. Many people with endometriosis experience “flares” during menstruation, and uterine fibroids can intensify bleeding and cramping at the same time. Understanding how these two common conditions overlap—and how they differ—can help you get the right diagnosis and relief.

Endometriosis vs. Uterine Fibroids: The Basics

Endometriosis occurs when tissue similar to the uterine lining grows outside the uterus—on the ovaries, fallopian tubes, peritoneum, bowel, or bladder. These implants respond to monthly hormones and can cause inflammation, scarring, and pain.

Uterine fibroids (leiomyomas) are noncancerous growths of muscle and fibrous tissue in the uterus. They vary in size and location (inside the uterine cavity, within the wall, or on the outer surface) and often cause heavy periods, pelvic pressure, or pain.

Both conditions are common. The National Institutes of Health estimates endometriosis affects about 11% of U.S. women aged 15–44, while the Office on Women’s Health notes that many women develop fibroids by age 50, with prevalence increasing with age until menopause. They can occur separately—or together.

Why Do Periods Trigger Endometriosis Flares?

Endometriosis pain often worsens during the period because:

• Inflammation rises: When hormone levels drop just before menstruation, endometriosis implants can bleed and release inflammatory molecules, sensitizing nearby nerves.
• Prostaglandins surge: These chemical messengers cause uterine contractions and pain. Elevated prostaglandins are linked to cramping and gastrointestinal symptoms during menses.
• Central sensitization: Ongoing pelvic inflammation can heighten the nervous system’s response to pain over time, making flares feel more intense.

How Fibroids Affect Your Period—and Your Pain

Fibroids don’t “flare” in the same way as endometriosis, but they can make periods heavier, longer, and more painful. Mechanisms include:

• Heavier bleeding: Submucosal or large fibroids increase the uterine surface area and disrupt normal contractions, leading to heavy menstrual bleeding and clots.
• Cramping and pressure: The uterus may contract more forcefully to expel blood, intensifying cramps. Fibroids can also cause bulk symptoms—pelvic pressure, back pain, urinary frequency, or constipation—especially when large.
• Acute degeneration pain: Rapid growth or reduced blood supply to a fibroid can cause sharp, localized pain.

When endometriosis and fibroids coexist, people often report severe cramping, pelvic pain before and during the period, and heavy bleeding.

Symptoms: Clues to Endometriosis, Fibroids, or Both

Symptoms can overlap, but common patterns include:

• More suggestive of endometriosis: Significant pelvic pain before and during periods; pain with sex (deep penetration); bowel or bladder pain around menses; infertility; chronic pelvic pain not limited to period days.
• More suggestive of fibroids: Heavy or prolonged periods (needing to change pads/tampons every 1–2 hours, passing large clots); pelvic pressure or a feeling of fullness; urinary frequency; constipation; visible abdominal enlargement.
• Possible in both: Painful periods (dysmenorrhea), lower back pain, fatigue from anemia (more common with fibroids due to heavy bleeding).

Warning signs to seek care promptly include soaking through protection hourly for several hours, fainting, severe one-sided pain, fever, or symptoms of anemia (shortness of breath, palpitations, dizziness).

Getting the Right Diagnosis

A thorough evaluation typically includes:

• History and pelvic exam: Your clinician will ask about timing of pain, bleeding volume, bowel/bladder symptoms, sexual pain, and fertility goals.
• Imaging for fibroids: Pelvic ultrasound is first-line to identify and map fibroids. MRI may be used to clarify size, number, and location before procedures.
• Assessment for endometriosis: Ultrasound can identify ovarian endometriomas but often misses superficial or deep lesions. A definitive diagnosis traditionally requires laparoscopy with visualization and, ideally, biopsy. Many clinicians use a “clinical diagnosis” based on symptoms and response to therapy when surgery isn’t immediately planned, consistent with professional guidance.

Managing Pain and Bleeding: Evidence-Based Options

Treatment is tailored to your symptoms, diagnosis, and reproductive plans. Options include:

Self-care and nonprescription measures

• NSAIDs (ibuprofen, naproxen) started 24 hours before the period can reduce prostaglandins and pain. Ask your clinician about dosing and safety if you have kidney, GI, or bleeding risks.
• Heat, gentle movement, and stress reduction (e.g., stretching, walking, mindfulness) may ease cramps and pelvic floor tension.
• Iron-rich nutrition and supplements if iron-deficiency anemia is present due to heavy bleeding (confirm with lab testing).

Hormonal therapies

• Combined hormonal contraception (pill, patch, ring) or progestin-only methods (pills, injection, implant) can lighten periods and relieve endometriosis-related pain by suppressing ovulation and stabilizing endometrial tissue.
• Levonorgestrel-releasing IUD can markedly reduce bleeding from fibroids (especially smaller intracavitary lesions) and improve cramps; it may also help some endometriosis symptoms.
• GnRH analogs temporarily lower estrogen to reduce pain and bleeding. These include agonists (e.g., leuprolide) and antagonists:
• Elagolix is FDA-approved for moderate to severe endometriosis pain. It can reduce pain but may cause low-estrogen side effects (hot flashes, bone mineral density loss) and is typically time-limited.
• Relugolix/estradiol/norethindrone acetate (a combination sometimes referred to by brand name) is FDA-approved to reduce heavy menstrual bleeding due to fibroids and is also approved for endometriosis-associated pain. The built-in “add-back” hormones help protect bone density and manage side effects.
• Therapy choices depend on your goals, side-effect tolerance, other health conditions, and whether you’re trying to conceive. Your clinician can review benefits, risks, and duration limits set by the FDA for specific medications.

Procedures and surgery

• For endometriosis: Laparoscopic excision or ablation of lesions can reduce pain and improve fertility in selected patients. Pelvic floor physical therapy may help residual muscle pain.
• For fibroids: Options include myomectomy (fibroid removal, uterus preserved), uterine artery embolization (shrinks fibroids by blocking blood supply), MRI-guided focused ultrasound, and hysterectomy for definitive treatment when childbearing is complete. The best choice depends on fibroid size, number, location, and reproductive plans.

Living With Both Conditions

If you have endometriosis and fibroids, a combined approach often works best—addressing inflammation and pain control for endometriosis while managing bleeding and bulk symptoms from fibroids. Track your symptoms (pain timing, flow, medication use), bring the log to visits, and discuss priorities—pain relief, bleeding control, fertility, or avoiding surgery—so your care plan reflects what matters most to you.

When to See a Clinician

Schedule a visit if:

• Period pain disrupts work, school, sleep, sex, or daily activities.
• You have heavy bleeding (soaking protection hourly, large clots, or periods lasting more than 7 days).
• You’re having difficulty getting pregnant.
• You have new or rapidly worsening pelvic pain.

Early evaluation can shorten time to diagnosis and expand your treatment options.

Key Takeaways

• Endometriosis commonly flares around the period due to inflammation and prostaglandins; fibroids intensify bleeding and cramps.
• Symptoms overlap, but heavy bleeding and pressure suggest fibroids, while cyclical pelvic pain, pain with sex, or bowel/bladder pain around menses suggest endometriosis.
• Ultrasound identifies fibroids; laparoscopy remains the gold standard for definitive endometriosis diagnosis, though many are treated based on clinical findings.
• Effective treatments range from NSAIDs and hormonal therapy to minimally invasive procedures and surgery—personalized to your goals.

Trusted Sources

• NIH, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD): Endometriosis
• U.S. Office on Women’s Health (HHS): Uterine Fibroids
• American College of Obstetricians and Gynecologists (ACOG): Endometriosis FAQ and Uterine Fibroids FAQ
• U.S. Food and Drug Administration (FDA): Elagolix (ORILISSA) Prescribing Information; FDA approval for relugolix/estradiol/norethindrone for endometriosis pain; Information on medicines for fibroids and endometriosis

This article is informational and not a substitute for personalized medical advice. Always discuss diagnosis and treatment decisions with your healthcare professional.