Uterine fibroids (leiomyomas or myomas) are common, non-cancerous tumors that develop from the smooth muscle tissue of the uterus during a woman’s reproductive years. Fibroids are classified by their location within the uterine structure, which determines the type and severity of symptoms. The intramural subtype is the most frequently observed, growing directly within the muscular uterine wall. This specific positioning leads to the unique effects and management considerations associated with intramural fibroids.
What Defines Intramural Fibroids
The uterus has three layers: the outer serosa, the inner endometrium, and the thick, middle muscular layer called the myometrium. Intramural fibroids develop and grow exclusively within the myometrium, embedded in the dense muscle tissue that forms the bulk of the uterine wall.
This location differentiates them from other fibroid types, such as subserosal fibroids, which project outward, and submucosal fibroids, which bulge inward beneath the uterine lining. Intramural fibroids are the most common type of uterine fibroid and can be found anywhere in the myometrium, including the anterior, posterior, or fundal regions. They often do not cause symptoms.
The size of these growths varies dramatically, ranging from microscopic to masses large enough to distort the overall shape of the uterus. As an intramural fibroid expands, it can cause the uterus to enlarge, potentially leading to pressure on nearby organs. Substantial growth can also push inward toward the uterine cavity or outward toward the outer surface, sometimes resulting in a hybrid classification.
How Intramural Fibroids Affect the Body
The location of intramural fibroids deep within the muscular wall influences the symptoms they produce, mainly by interfering with the uterus’s ability to contract effectively. A frequent clinical consequence is excessive menstrual bleeding, known as menorrhagia. These masses can increase the surface area of the uterine lining and disrupt blood vessels, leading to prolonged and heavier periods.
Chronic heavy bleeding often results in iron-deficiency anemia. Continuous blood loss depletes the body’s iron stores, causing persistent fatigue, weakness, and shortness of breath.
Intramural fibroids can also cause significant pelvic discomfort and pressure, especially as they increase in size. Large fibroids exert mechanical pressure on surrounding structures, leading to symptoms like pelvic fullness or bloating. If fibroids press against the bladder, they can cause frequent urination or difficulty emptying the bladder completely.
Pressure exerted by large posterior intramural fibroids can result in chronic backaches. For individuals planning a family, intramural fibroids, particularly those larger than six centimeters or those that distort the uterine cavity, can present reproductive challenges. They may impair fertility by interfering with sperm transport or embryo implantation, and they can also increase the risk of complications during pregnancy.
Current Approaches to Managing Intramural Fibroids
Management of intramural fibroids depends on symptom severity, the size and number of growths, and the person’s desire for future fertility. For individuals with mild or no symptoms, a strategy of watchful waiting (expectant management) is appropriate, involving regular monitoring without immediate intervention. Treatment is generally reserved for those whose symptoms significantly affect their health and daily life.
Medical management focuses on controlling symptoms, particularly heavy menstrual bleeding. Hormonal therapies, such as combined oral contraceptives or progestins, help regulate the menstrual cycle and reduce blood flow. Gonadotropin-releasing hormone (GnRH) agonists and antagonists are also used. These medications temporarily suppress estrogen production, which can shrink fibroids and reduce bleeding, though they are usually prescribed for short-term use.
For definitive treatment, several procedural and surgical options are available. Myomectomy is a fertility-sparing surgery designed to remove the fibroids while preserving the uterus, making it a common choice for those who wish to become pregnant. Intramural fibroids can be removed via traditional abdominal surgery, laparoscopy, or robotic assistance, depending on their size and location within the muscle wall.
Minimally invasive, non-surgical options include Uterine Artery Embolization (UAE). This procedure involves injecting tiny particles into the blood vessels supplying the fibroid, blocking blood flow and causing the fibroid to shrink and symptoms to improve. Another option is Magnetic Resonance-guided Focused Ultrasound Surgery (MRgFUS), which uses high-intensity ultrasound waves to destroy the fibroid tissue without incisions. The final surgical option for those who have completed childbearing is a hysterectomy, which involves the complete removal of the uterus.