Uterine fibroids are non-cancerous growths that develop within or on the uterus. Also known as leiomyomas or myomas, these growths are composed of muscle and fibrous tissue. Many individuals with fibroids do not experience symptoms, while others may have painful or heavy periods. They can vary significantly in size, ranging from tiny, almost invisible seedlings to growths large enough to alter the shape of the uterus.
The Nature of Fibroid Growth
The growth rate of uterine fibroids is highly variable. Some fibroids may grow slowly over months or years, increasing by only a few millimeters or centimeters, while others can experience rapid growth, even doubling in size within a few months. Research suggests that the growth rate can range from 18% to 120% per year.
Fibroids do not always grow; some may remain stable in size for extended periods, and others might shrink spontaneously. This shrinking is common after menopause, when hormone levels decline. Very small fibroids may sometimes grow faster than larger ones.
What Influences Fibroid Growth
Hormonal influences play a role in fibroid growth. Estrogen and progesterone are the primary hormones that stimulate fibroid development and enlargement. Fibroid cells contain more receptors for these hormones than normal uterine muscle cells, making them more responsive to hormonal fluctuations. Fibroids often grow larger during pregnancy when estrogen and progesterone levels surge, and tend to shrink after menopause when these hormone levels decrease.
Genetic predisposition also influences fibroid development. If a close family member, such as a mother or sister, has had fibroids, an individual’s risk can be about three times higher than average. Specific genetic variations associated with fibroid development suggest a hereditary component. Other factors that may influence fibroid growth include age, with fibroids typically developing during reproductive years, and obesity, which can increase estrogen levels.
Recognizing Symptoms of Growth
Fibroid growth can be inferred from changes in symptoms. Common symptoms include heavy menstrual bleeding, prolonged periods, pelvic pressure or pain, and increased urinary frequency. An increase in the severity or frequency of these symptoms can suggest that fibroids are growing.
If heavy bleeding becomes more severe or occurs more frequently, it might indicate fibroid expansion. Increased abdominal distension, a feeling of fullness, or new pressure on the bladder can signal that fibroids are growing and pressing on surrounding organs. The severity of symptoms often correlates with the size and location of the fibroids.
How Fibroid Growth is Monitored
Healthcare providers monitor fibroid growth using medical imaging. Ultrasound is a standard tool for detecting and tracking changes in fibroid size and location. During an ultrasound, sound waves create images of the uterus and fibroids.
In some situations, a magnetic resonance imaging (MRI) scan may be used to provide more detailed images of fibroids. MRI can help differentiate fibroids from other conditions. Beyond imaging, healthcare providers also assess symptoms, as changes in their intensity or nature can indicate fibroid growth and guide monitoring frequency and treatment decisions.