Endometriosis and Fibroids: What to Know

Endometriosis and uterine fibroids are two of the most common gynecologic conditions affecting people in their reproductive years. Both are benign (noncancerous), yet they can cause significant pain, heavy menstrual bleeding, and fertility challenges. Understanding how they are similar, how they differ, and the full range of diagnostic and treatment options can help you make informed decisions with your clinician.

At a Glance: How They Compare

• What they are
  • Endometriosis: Tissue similar to the uterine lining grows outside the uterus (e.g., on ovaries, fallopian tubes, pelvic peritoneum), triggering inflammation and scarring.
  • Fibroids: Noncancerous muscular tumors (leiomyomas) that grow in or on the uterine wall; they vary in number, size, and location.
• How common
  • Endometriosis: Affects about 1 in 10 people of reproductive age.
  • Fibroids: By age 50, up to 70% of people may have fibroids; risk is higher and symptoms often more severe among Black women.
• Key symptoms
  • Endometriosis: Pelvic pain (often cyclic), painful periods, pain with sex, painful bowel movements or urination during menses, infertility.
  • Fibroids: Heavy or prolonged periods, pelvic pressure or pain, frequent urination, constipation, anemia, reproductive issues depending on location.
• Cancer risk: Both conditions are benign; malignant transformation of fibroids is very rare.

Symptoms and When to Seek Care

Track your cycle and symptoms to spot patterns. Seek medical care if you experience any of the following:

• Severe menstrual pain that limits daily activities
• Heavy bleeding (e.g., soaking a pad or tampon every hour for several hours, passing large clots)
• Bleeding between periods or after sex
• Pain during or after intercourse
• Persistent pelvic pressure, urinary frequency, or constipation
• Difficulty getting pregnant after 6–12 months of trying
• Signs of anemia (fatigue, shortness of breath, dizziness)

Causes and Risk Factors

Endometriosis

The exact cause is not fully understood. Theories include retrograde menstruation, immune dysfunction, and cellular transformation. Risk factors can include family history, early menarche, short menstrual cycles, and heavy or prolonged periods.

Fibroids

Fibroid growth is influenced by hormones (estrogen and progesterone) and genetic changes in uterine muscle cells. Risk factors include age (30s–40s), family history, Black race, early menarche, obesity, and hypertension.

How Doctors Make the Diagnosis

Endometriosis

• Clinical evaluation: Symptom history and pelvic exam.
• Imaging: Transvaginal ultrasound can identify ovarian endometriomas; MRI sometimes helps with deep infiltrating disease.
• Definitive diagnosis: Laparoscopy with tissue confirmation remains the gold standard, though many patients are treated based on clinical findings and imaging.

Fibroids

• Pelvic exam may detect an enlarged or irregular uterus.
• Transvaginal ultrasound is first-line imaging; MRI is useful for complex cases or planning procedures.
• Hysteroscopy or saline infusion sonography can better evaluate fibroids inside the uterine cavity (submucosal).

Treatment Options

Therapy is tailored to your symptoms, goals (e.g., pain control, fertility), and medical history. Many options are reversible; some are definitive. Discuss benefits, risks, and side effects with your clinician.

Endometriosis Treatments

• Pain relief: NSAIDs (e.g., ibuprofen, naproxen) can reduce menstrual pain.
• Hormonal suppression:
  • Combined hormonal contraceptives (pill, patch, ring)
  • Progestin-only options (pills, injection, implant, levonorgestrel IUD)
  • GnRH antagonists (e.g., elagolix) to reduce estrogen and relieve pain; often used with add-back therapy to protect bone health
  • GnRH agonists (e.g., leuprolide) for short-term suppression
  • Aromatase inhibitors in select cases
• Surgery: Laparoscopic excision or ablation of lesions and lysis of adhesions can improve pain and, in some cases, fertility.
• Fertility management: Timed intercourse, ovulation induction, intrauterine insemination, or IVF depending on severity and other factors.

Fibroid Treatments

• Watchful waiting: Appropriate if symptoms are mild and anemia is absent.
• Medications for bleeding and pain:
  • NSAIDs for cramps
  • Tranexamic acid (non-hormonal) taken during menses
  • Hormonal contraceptives or levonorgestrel IUD to lighten or control bleeding
  • GnRH antagonists with add-back therapy (e.g., Oriahnn, Myfembree) to reduce heavy menstrual bleeding due to fibroids
  • Short-term GnRH agonists (e.g., leuprolide) to shrink fibroids preoperatively
• Uterus-sparing procedures:
  • Myomectomy: Surgical removal of fibroids (hysteroscopic, laparoscopic, or open), preserves the uterus and fertility potential.
  • Uterine artery embolization (UAE): Minimally invasive; shrinks fibroids by blocking their blood supply.
  • Radiofrequency ablation: Heat-based destruction of fibroid tissue (e.g., laparoscopic or transcervical approaches).
  • MRI-guided focused ultrasound: Noninvasive thermal ablation for select candidates.
• Definitive option: Hysterectomy eliminates fibroids and bleeding; appropriate when childbearing is complete and other treatments are ineffective or unsuitable.

Fertility and Pregnancy Considerations

Both conditions can affect fertility, but many people conceive and carry healthy pregnancies with appropriate care.

• Endometriosis: Inflammation and scarring can impair egg pickup, tubal function, or implantation. Surgical treatment of moderate to severe disease may improve fertility for some. Assisted reproductive technologies (e.g., IVF) are effective options.
• Fibroids: Impact depends on size and location. Submucosal fibroids that distort the uterine cavity are most strongly linked to infertility and miscarriage; hysteroscopic myomectomy can improve outcomes. During pregnancy, fibroids can increase risks of pain, malpresentation, preterm birth, and cesarean delivery, but many pregnancies proceed without major complications.

Living Well with Endometriosis or Fibroids

• Track symptoms with a period/pain diary to guide treatment decisions.
• Address anemia if bleeding is heavy; ask about iron studies and supplementation.
• Pelvic floor physical therapy and mind–body strategies (heat, pacing, CBT-based pain coping) may help with chronic pain.
• Shared decision-making is essential: discuss goals (pain relief, fertility, uterine preservation) and what “success” looks like for you.
• Find the right specialist: For complex cases, consider a gynecologist with expertise in endometriosis excision, minimally invasive surgery, or fibroid-focused care.

Trusted Sources and Further Reading

• NIH/NICHD – Endometriosis Overview: https://www.nichd.nih.gov/health/topics/endometriosis
• NIH/NICHD – Uterine Fibroids Overview: https://www.nichd.nih.gov/health/topics/uterine-fibroids
• ACOG – Endometriosis FAQ: https://www.acog.org/womens-health/faqs/endometriosis
• ACOG – Uterine Fibroids FAQ: https://www.acog.org/womens-health/faqs/uterine-fibroids
• FDA – Orilissa (elagolix) for endometriosis pain: https://www.fda.gov/drugs/postmarket-drug-safety-information-patients-and-providers/orilissa-elagolix
• FDA – Oriahnn (elagolix/estradiol/norethindrone) for fibroid-related bleeding: https://www.fda.gov/drugs/drug-safety-and-availability/oriahnn-elagolix-estradiol-and-norethindrone-acetate-capsules
• FDA – Myfembree (relugolix/estradiol/norethindrone): https://www.fda.gov/drugs/drug-safety-and-availability/myfembree-relugolix-estradiol-and-norethindrone-acetate-tablets

This article is for educational purposes and does not replace personalized medical advice. If you have symptoms suggestive of endometriosis or fibroids, consult a qualified healthcare professional.