A fibroid, also known as a uterine fibroid, uterine leiomyoma, or myoma, is a non-cancerous tumor made up of muscle and fibrous tissue that develops in or on the walls of the uterus (womb). These growths can vary in size from as small as an apple seed to as large as a grapefruit or even bigger. A person can have one fibroid or multiple fibroids at the same time. Fibroids are common, especially in women of reproductive age (typically between 30 and menopause), and they are usually influenced by hormone levels, particularly estrogen. They often cause no symptoms and may be found incidentally during examinations or scans. However, when symptoms do occur, they can include:

• Heavy or prolonged menstrual periods
• Painful periods
• Lower back or leg pain
• Pelvic pain or a feeling of fullness
• Frequent urination
• Constipation
• Pain during sexual intercourse
• Fertility or pregnancy complications in some cases

Fibroids are classified based on their location in the uterus, such as subserosal (outside the uterine wall), intramural (within the muscular wall), or submucosal (growing into the uterine cavity). Though fibroids are almost always benign, very rarely, they can be cancerous. Treatment may not be necessary if there are no symptoms, but options are available when fibroids cause problems, including medications and surgery. Overall, fibroids are very common benign tumors that affect many women but do not typically pose serious health risks unless symptomatic or very large.