Uterine Fibroids

Overview

Uterine fibroids are noncancerous growths that develop from the muscular wall of the uterus (womb). They are made of muscle and fibrous tissue and can range in size from too small to see to large masses that can enlarge and distort the uterus. Fibroids are very common, especially during the reproductive years, and many women have one or more at some point. The number, size, and location of fibroids vary widely from person to person.

Many fibroids cause no symptoms and are discovered by chance during a pelvic examination or imaging done for another reason. When symptoms do occur, they often relate to heavy menstrual bleeding and pelvic pressure. Fibroids are almost always benign and only very rarely cancerous. Their growth is influenced by hormones, and they tend to shrink after menopause. A wide range of treatments is available, from watchful waiting to medication and procedures, chosen based on symptoms and personal goals.

Symptoms

Many fibroids cause no symptoms. When they do, common symptoms include:

• Heavy or prolonged menstrual bleeding, sometimes with clots, which can lead to iron-deficiency anemia.
• Pelvic pressure or fullness, and an enlarged or bloated lower abdomen.
• Frequent urination or difficulty emptying the bladder if a fibroid presses on it.
• Constipation or pressure on the bowel.
• Pelvic or low back pain, and pain during sex in some cases.
• Menstrual cramps.

Symptoms depend largely on the size and location of the fibroids. Very heavy bleeding that causes fatigue, dizziness, or shortness of breath from anemia, or sudden severe pelvic pain, should be evaluated promptly.

Causes

The exact cause of fibroids is not fully understood, but several factors are known to influence their development and growth:

• Hormones: Estrogen and progesterone, the hormones that regulate the menstrual cycle, promote fibroid growth, which is why fibroids tend to grow during the reproductive years and shrink after menopause.
• Genetics: Fibroids often run in families, and changes in certain genes are found in fibroid tissue.
• Growth factors: Substances that help the body maintain tissues may encourage fibroid growth.

Fibroids develop from a single muscle cell in the uterine wall that grows and multiplies. They are not caused by anything a person did, and having fibroids does not mean a higher risk of uterine cancer.

Risk Factors

• Being of reproductive age, with fibroids most common in the 30s and 40s
• A family history of fibroids
• Being of African descent, who tend to develop fibroids more often and earlier
• Obesity
• Starting periods at an early age
• Diet factors and vitamin D deficiency in some studies

Diagnosis

Fibroids are often found during a routine pelvic examination and confirmed with imaging:

• Pelvic examination: May reveal an enlarged or irregularly shaped uterus.
• Ultrasound: The most common imaging test to confirm fibroids and measure their size and location.
• Other imaging: MRI can provide detailed mapping, and specialized ultrasound or scope procedures can assess fibroids affecting the uterine cavity.
• Blood tests: To check for anemia if bleeding is heavy.

Treatment

Treatment depends on symptoms, fibroid size and location, age, and whether you wish to preserve fertility. Options include:

• Watchful waiting: For fibroids that cause no or minimal symptoms, since many do not need treatment and shrink after menopause.
• Medications: Hormonal treatments and other medicines to control heavy bleeding and reduce symptoms, and iron for anemia.
• Minimally invasive procedures: Such as uterine artery embolization, which cuts off the fibroid's blood supply, and other techniques to destroy fibroid tissue.
• Surgery: Myomectomy removes fibroids while preserving the uterus, and hysterectomy removes the uterus and is a definitive treatment for those who no longer wish to become pregnant.

A doctor can help weigh the benefits and risks of each option according to your symptoms and goals.

Prevention

There is no proven way to prevent fibroids, since their development is influenced by hormones and genetics. However, some general measures support overall reproductive health:

• Maintain a healthy weight, as obesity is associated with fibroids
• Eat a balanced diet rich in fruits and vegetables
• Stay physically active
• Attend regular gynecologic checkups so fibroids and symptoms can be monitored
• Report heavy bleeding or new pelvic symptoms to your doctor

When to See a Doctor

See a doctor if you have heavy or prolonged periods, pelvic pressure or pain, frequent urination, or other bothersome symptoms. It is especially important to seek care if you have:

• Very heavy bleeding, or bleeding with tiredness, dizziness, or shortness of breath, which may signal anemia
• Sudden, severe pelvic pain
• Bleeding between periods or after menopause, which always needs evaluation

Prompt evaluation helps confirm the diagnosis, treat anemia, and choose the most suitable management.

Related Topics

Frequently Asked Questions

References

1. Office on Women's Health, U.S. Department of Health and Human Services. Uterine fibroids.
2. Mayo Clinic. Uterine fibroids — Symptoms and causes.
3. National Institute of Child Health and Human Development (NICHD). Uterine Fibroids.
4. MedlinePlus, U.S. National Library of Medicine. Uterine fibroids.