Uterine fibroids are common, non-cancerous growths that originate within the muscle tissue of the uterus. They are the most frequent type of benign tumor found in the female reproductive system, affecting a significant percentage of people of childbearing age. Because fibroids vary widely in size and location, they often lead to confusion regarding their nature and behavior inside the body.
Understanding Fibroid Structure and Attachment
The short answer is that fibroids are fixed growths that do not float freely within the body. Fibroids are solid tumors composed primarily of smooth muscle cells and fibrous connective tissue, similar to a dense knot. They develop directly from a stem cell within the myometrium, the thick muscular wall of the uterus.
This structure ensures their fixed attachment, as the fibroid grows into and from the uterine muscle. The fibroid mass is supplied with blood, which further anchors it to the organ’s structure. While the uterus is a mobile organ that can shift position within the pelvis, the fibroid mass remains bound to the specific site where it began to grow.
These growths are heavily influenced by hormones, particularly estrogen and progesterone, which stimulate their development. Fibroids are dense and firm, and although they do not move, they can increase in size or shrink over time, especially after menopause when hormone levels drop significantly.
Classifications Based on Uterine Placement
The specific location where a fibroid is anchored within the uterus determines its classification. This placement also significantly influences the symptoms experienced by the patient.
Intramural fibroids are the most common type, developing within the muscular wall of the uterus itself. As they grow, these fibroids can cause the entire uterus to become enlarged, leading to general pelvic pain and pressure.
Subserosal fibroids form on the outer surface of the uterus, growing outward into the pelvic or abdominal cavity. This type often causes symptoms related to pressure on nearby organs, such as frequent urination or constipation.
Submucosal fibroids are situated just beneath the endometrium, the inner lining of the uterus, and protrude into the uterine cavity. Even when relatively small, submucosal fibroids are the most likely to cause significant symptoms, especially heavy and prolonged menstrual bleeding. A variation is a pedunculated fibroid, which is attached to the uterus by a narrow, stalk-like structure.
Common Signs and Symptoms
While many fibroids cause no noticeable symptoms, those that do can affect quality of life. The most frequently reported symptom is heavy or prolonged menstrual bleeding, known as menorrhagia, which can sometimes lead to iron-deficiency anemia.
The mass effect of larger fibroids often results in chronic pelvic pain and a feeling of fullness or pressure in the lower abdomen. Pressure on surrounding structures can manifest as frequent or difficult urination due to bladder compression. Pressure on the bowel can also result in backache and constipation.
In some cases, fibroids can interfere with reproductive health, complicating pregnancy or making it more difficult to conceive. Rarely, a fibroid can outgrow its blood supply and begin to degenerate, causing sudden, acute pain.
Management and Treatment Options
The approach to managing fibroids depends on the severity of symptoms, the fibroid’s location, and the patient’s desire for future fertility. For individuals with no or mild symptoms, a strategy of “watchful waiting” is often recommended, as fibroids are benign and may shrink after menopause.
Hormonal medications, such as Gonadotropin-releasing hormone (GnRH) agonists, are sometimes used to temporarily shrink fibroids and reduce symptoms by creating a temporary, menopause-like state. Other hormonal options, like progestin-releasing intrauterine devices (IUDs), can help manage heavy bleeding but do not shrink the fibroids themselves.
Minimally invasive procedures offer alternatives to traditional surgery. Uterine Fibroid Embolization (UFE) involves injecting small particles to block the blood supply to the fibroids, causing them to shrink. Radiofrequency ablation uses heat energy to destroy and shrink the fibroid tissue.
Surgical options range from myomectomy, which removes only the fibroids while preserving the uterus for future fertility, to hysterectomy, the complete removal of the uterus, which provides a definitive cure. The type of myomectomy performed, such as hysteroscopic or laparoscopic, depends on the fibroid’s size and specific placement within the uterine layers.