Uterine Fibroids (Leiomyomas)
Understanding the most common benign gynecologic tumors affecting up to 80% of women by menopause
Seek Emergency Care If You Experience:
- β’Sudden severe pelvic or abdominal pain
- β’Heavy bleeding soaking through a pad or tampon every hour for several hours
- β’Severe abdominal pain with fever (could indicate fibroid degeneration with infection)
- β’Signs of severe anemia: extreme fatigue, dizziness, fainting, rapid heartbeat
Call 911 or go to the nearest emergency room immediately. Do not delay care.
What They Are
Uterine fibroids (also called leiomyomas or myomas) are benign (non-cancerous) smooth muscle tumors that grow from the muscle wall of the uterus. They are the most common pelvic tumors in women, with diagnoses in 50-70% of women by menopause, and rates exceeding 80% in Black women.
Fibroids can range from tiny seedlings smaller than a grain of rice to large masses that can enlarge and distort the uterus. Most women have multiple fibroids. While 70-80% of women will develop fibroids, only 25-30% experience significant symptoms.
Why They Matter
When symptomatic (about 30% of cases), fibroids can cause:
- Heavy menstrual bleeding leading to anemia and significant lifestyle disruption
- Pelvic pressure and pain affecting daily comfort and activities
- Urinary and bowel dysfunction from pressure on surrounding organs
- Fertility challenges in 5-10% of infertility cases
Fibroids are the leading indication for hysterectomy in the United States, accounting for 39% of all hysterectomies. Black women face a disproportionate burden, developing fibroids at younger ages, with larger and more numerous tumors, and more severe symptoms.
Common Symptoms (When Present)
- Heavy menstrual bleeding (HMB) - most common symptom
- Prolonged periods (lasting more than 7 days)
- Pelvic pain and pressure
- Pelvic or abdominal fullness, bloating ("looking pregnant")
- Urinary frequency, urgency, or retention
- Constipation or difficulty with bowel movements
- Low back pain
- Painful intercourse (dyspareunia)
- Anemia from chronic blood loss
Note: 70% of women with fibroids are asymptomatic. Fibroids are often discovered incidentally during pelvic exams or imaging for other reasons.
Types and Locations
Fibroids are classified by their location in or on the uterus, which affects symptoms and treatment options. The International Federation of Gynecology and Obstetrics (FIGO) classification system categorizes fibroids into types 0-8.
Submucosal (Types 0-2)
Project into the uterine cavity. Most likely to cause heavy bleeding even when small. May interfere with fertility and implantation.
Intramural (Types 3-4)
Located within the uterine wall. Can cause uterine enlargement, pressure symptoms, and heavy bleeding. Most common type.
Subserosal (Types 5-7)
Project outward from the outer surface of the uterus. May cause pressure symptoms but less likely to cause heavy bleeding. Can become very large.
Other (Type 8)
Cervical fibroids, broad ligament fibroids, or other unusual locations.
Why They're Often Missed or Dismissed
Diagnostic Challenges:
- Normalization of heavy bleeding: Women are often told heavy periods are "just how some women are"
- Racial disparities: Black women experience diagnostic delays despite higher prevalence and severity
- Asymptomatic cases: Many fibroids cause no symptoms and are never diagnosed
- Multiple contributing factors: Heavy bleeding and pain may be attributed to other causes
How They're Typically Evaluated
First-Line Evaluationβββ
Pelvic examination + transvaginal ultrasound (TVUS): Ultrasound is the preferred initial imaging modality. Can detect fibroids, determine number, size, and location.
Detailed Imagingβββ
MRI: Most accurate imaging (99% sensitivity). Used for:
- β’ Surgical planning
- β’ Distinguishing fibroid types and locations
- β’ Detecting fibroid degeneration
- β’ Mapping blood supply for embolization procedures
For Submucosal Fibroids
Saline infusion sonography (SIS): Fluid instilled into uterus during ultrasound to better visualize submucosal fibroids that project into the cavity.
Treatment Options
Treatment depends on symptoms, fibroid size and location, desire for future pregnancy, and proximity to menopause. Many options exist between watchful waiting and hysterectomy. This is educational information only - treatment decisions should be made with your healthcare provider.
Expectant Management (Observation)
Recommended for asymptomatic fibroids. Most fibroids shrink after menopause. Regular monitoring with periodic exams or imaging.
Medical Managementβββ
- Hormonal contraceptives: Combined pills, progestin IUD. Help control heavy bleeding.
- Tranexamic acid: Reduces menstrual bleeding by 40-50%.
- NSAIDs: Reduce pain and may decrease bleeding.
- GnRH agonists/antagonists: Temporarily shrink fibroids. Used pre-operatively or short-term (cause menopause-like side effects).
Minimally Invasive Proceduresββ
- Uterine artery embolization (UAE): Blocks blood supply to fibroids, causing them to shrink. Preserves uterus.
- MRI-guided focused ultrasound (MRgFUS): Non-invasive ablation using high-intensity ultrasound waves.
- Endometrial ablation: Destroys uterine lining to reduce bleeding (for small submucosal fibroids).
Note: Long-term efficacy data for some minimally invasive procedures is still emerging.
Surgical Optionsβββ
- Myomectomy: Surgical removal of fibroids while preserving the uterus. Preferred for women desiring future pregnancy. Can be done via laparoscopy, hysteroscopy (for submucosal), or open surgery. Recurrence is common - many require repeat procedures.
- Hysterectomy: Definitive treatment. Removal of uterus eliminates fibroid symptoms permanently. Vaginal approach preferred when feasible (faster recovery than abdominal).
Important Considerations
Malignancy Risk
Leiomyosarcoma (malignant fibroid) occurs in less than 1% of cases (approximately 1 in 400 women with fibroids). Key points:
- β’ Rapid growth is NOT a reliable predictor of malignancy
- β’ Postmenopausal growth or new symptoms warrant higher suspicion
- β’ Most rapidly growing fibroids are still benign
When to Seek Medical Care
Urgent (Same Day/ER)
- β’ Sudden severe pelvic/abdominal pain
- β’ Bleeding soaking through a pad/hour for 2+ hours
- β’ Severe pain with fever (possible fibroid degeneration with infection)
- β’ Signs of severe anemia (fainting, rapid heartbeat, extreme fatigue)
Schedule Appointment
- β’ Heavy menstrual bleeding
- β’ Pelvic pressure or pain
- β’ Urinary frequency or constipation
- β’ Abdominal enlargement
- β’ Difficulty conceiving
What This Page Does NOT Replace
This educational content cannot and does not:
- β’ Diagnose fibroids or determine their type/location
- β’ Recommend which treatment option is best for you
- β’ Interpret your imaging results
- β’ Assess your individual malignancy risk
- β’ Replace consultation with a qualified healthcare provider
Treatment decisions require individualized assessment of your symptoms, fertility desires, age, and fibroid characteristics by your healthcare provider.
Key Takeaways
- Fibroids are benign tumors affecting 50-70% of women by menopause, and over 80% of Black women
- Only about 30% of women with fibroids experience significant symptoms
- Location (submucosal, intramural, subserosal) determines symptom pattern and treatment options
- Transvaginal ultrasound is the first-line imaging test; MRI offers the most detail
- Treatment ranges from observation to medication, minimally invasive procedures, or surgery
- Malignant transformation (leiomyosarcoma) is rare, occurring in less than 1% of cases
Related Resources
Health in Your 40s
Fibroid symptoms often peak in this decade. Learn about life stage-specific considerations.
Read More βEvidence Summary
Well-Established (βββ)
Prevalence and racial disparities, FIGO classification system, transvaginal ultrasound and MRI as diagnostic tools, myomectomy and hysterectomy as definitive surgical options, low malignancy risk
Emerging Evidence (ββ)
Long-term outcomes of uterine artery embolization and MRI-guided focused ultrasound, optimal candidate selection for fertility-preserving procedures
Research Gaps (β )
Underlying causes of racial disparities in fibroid development, best predictors of recurrence after myomectomy, optimal long-term management for women who decline surgery
Last Updated: January 2025