Uterine fibroids, also known as leiomyomas, are non-cancerous growths that develop from the muscle tissue of the uterus. They affect up to 80% of women by the time they reach menopause. While many individuals experience no noticeable symptoms, fibroids are a leading cause of abnormal uterine bleeding. These tumors can disrupt the menstrual cycle, often leading to substantial blood loss.
The Mechanism of Fibroid-Related Bleeding
Fibroid location dictates its potential to cause bleeding. Those growing into the uterine cavity are the most problematic. Submucosal fibroids, located beneath the inner lining (endometrium), compromise the integrity of the tissue shed during menstruation. Even small growths can cause severe bleeding by interfering with blood clotting and tissue repair.
A fibroid distorts the smooth muscle architecture, preventing the uterine wall from contracting effectively. These contractions normally compress blood vessels during the menstrual cycle, which helps stem blood flow. When this mechanism is inhibited by the fibroid mass, bleeding becomes prolonged and heavier.
Fibroids also promote localized changes in the vascular system. They stimulate angiogenic factors, encouraging the formation of new blood vessels. This results in a higher density of fragile blood vessels, often with wider diameters and thinner walls.
These altered vessels contribute to increased blood flow, making the tissue prone to rupture. Furthermore, the fibroid tissue can contain higher concentrations of hormone receptors. This may locally amplify estrogen effects, leading to thicker endometrial growth and a heavier monthly shed.
Characteristics of Abnormal Uterine Bleeding
The most recognized bleeding symptom is heavy menstrual bleeding (menorrhagia). This blood loss is defined as soaking through sanitary protection in an hour or less for several consecutive hours, or passing blood clots larger than a quarter. This excessive flow can be disruptive and often leads to iron-deficiency anemia.
Fibroids commonly cause prolonged menstruation, where the bleeding phase extends beyond seven days. A period lasting eight days or more is considered prolonged. This extended bleeding compounds the total volume of blood lost during a cycle.
Intermenstrual bleeding, or spotting between periods, can be a symptom. This is particularly true for fibroids that protrude into the uterine cavity or are attached by a stalk (pedunculated). Any bleeding outside the expected cycle window warrants evaluation.
Non-Bleeding Symptoms Associated with Fibroids
Fibroids can cause symptoms related to their size and the pressure they exert on surrounding organs. Many individuals report pelvic pressure or abdominal fullness, ranging from a dull ache to a constant sensation of heaviness. This occurs when fibroids grow large enough to increase the size of the uterus.
Fibroids can press against the bladder, leading to urinary frequency or urgency, as the organ’s capacity is reduced. If a fibroid is positioned toward the back of the uterus, it can press on the colon or rectum, causing chronic constipation or discomfort during bowel movements.
Pain is a common symptom, manifesting as painful menstrual cramping (dysmenorrhea) or chronic pelvic pain. Pain during sexual intercourse (dyspareunia) may occur, especially depending on fibroid location. In rare instances, a fibroid may outgrow its blood supply and degenerate, causing sudden, sharp pain.
Confirming the Diagnosis and Management Options
The first step in addressing fibroid symptoms is a consultation with a healthcare professional, involving a detailed review of menstrual history. The primary diagnostic tool is typically an ultrasound, which uses sound waves to create images of the uterus and pelvis. Both transabdominal and transvaginal techniques are effective for detecting and characterizing fibroids based on size, number, and location.
For complex cases or surgical planning, other imaging modalities like Magnetic Resonance Imaging (MRI) or a hysteroscopy may be employed. An MRI provides detailed soft-tissue images. A hysteroscopy allows a doctor to view the inside of the uterine cavity directly, which is useful for submucosal fibroids.
Management is highly individualized, depending on symptom severity, fibroid characteristics, and the desire for future fertility. For those with mild or no symptoms, watchful waiting may be recommended, as fibroids shrink after menopause.
Medical treatments are the first line of therapy for managing bleeding. Hormonal options, such as oral contraceptives or progestin-releasing intrauterine devices, can reduce heavy flow. Non-hormonal medications, like tranexamic acid, improve blood clotting, and nonsteroidal anti-inflammatory drugs (NSAIDs) can reduce both bleeding and pain.
When medical management is insufficient, minimally invasive procedures offer uterus-sparing options.
Minimally Invasive Procedures
Uterine Fibroid Embolization (UFE) involves injecting small particles into the blood vessels supplying the fibroids, cutting off blood flow and causing them to shrink. MRI-guided focused ultrasound surgery (MRgFUS) uses high-intensity sound waves to destroy the fibroid tissue.
Surgical Options
Surgical interventions include myomectomy, the removal of fibroids while leaving the uterus intact. This is a viable option for those who wish to maintain fertility. The definitive treatment is a hysterectomy, the complete removal of the uterus. This procedure is reserved for severe cases or for individuals who no longer desire children, as it permanently resolves all fibroid symptoms.