Uterine fibroids, also known as leiomyomas, are non-cancerous growths that develop from the muscle tissue of the uterus. These common tumors can vary significantly in size and number, yet their presence often disrupts the normal menstrual cycle. The location of a fibroid is the primary determinant of whether it will cause bleeding. When symptoms occur, they can range from slightly heavier periods to severely debilitating blood loss, requiring medical evaluation and treatment.
How Fibroids Disrupt the Menstrual Cycle
The physical positioning of the fibroid within the uterine wall is the most important factor influencing bleeding. Fibroids located just beneath the lining of the uterine cavity, known as submucosal fibroids, have the strongest association with heavy bleeding. They directly distort the inner surface where the menstrual blood originates. This distortion can physically compress or stretch the endometrium, leading to abnormal blood vessel formation and increased vascular fragility.
Fibroids also disrupt the physiological process the uterus uses to stop blood flow during menstruation. Normally, the muscular wall of the uterus contracts after the lining is shed to compress the blood vessels and staunch the bleeding. Large fibroids can interfere with this organized muscle contraction, preventing the uterus from effectively clamping down on the open blood vessels. This results in an extended and heavier flow.
Localized molecular changes within the uterus also contribute to bleeding. Fibroids can stimulate the growth of new blood vessels, a process called angiogenesis, leading to a higher overall blood flow into the uterine area. They may also increase local levels of certain growth factors and hormones, such as prostaglandins, which affect blood vessel dilation and clotting function. These combined mechanical and biochemical changes create an environment prone to sustained and excessive blood loss.
Recognizing Abnormal Uterine Bleeding Patterns
The primary symptom of fibroid-related bleeding is menorrhagia, defined as heavy menstrual bleeding. This often means soaking through one or more sanitary products every hour for several consecutive hours. Passing blood clots that are larger than a quarter is another common indicator of flow that is significantly heavier than normal.
Fibroids frequently cause periods that are prolonged, often lasting more than seven or eight days. In addition to heavy flow, some individuals may also experience intermenstrual bleeding, which is spotting or bleeding that occurs between expected cycles. This unpredictable pattern can be disruptive and is sometimes referred to as metrorrhagia.
Chronic, excessive blood loss can lead to a complication called iron-deficiency anemia. The constant depletion of iron stores results in symptoms such as profound fatigue, weakness, and shortness of breath. For many women, the severity of the bleeding and the resulting anemia are the primary reasons for seeking medical intervention.
Confirming Fibroids as the Cause
A medical evaluation is necessary to confirm that fibroids are the source of the abnormal bleeding and to exclude other potential causes. The initial diagnostic step is typically a pelvic ultrasound, which uses sound waves to create images of the uterus. Both transabdominal and transvaginal techniques are often used to map the size, number, and precise location of the fibroids.
Standard ultrasound may not provide a clear view of fibroids that protrude slightly into the uterine cavity. For this reason, a doctor may recommend a saline-infusion sonography (SIS), also known as a hysterosonogram. Sterile saline is injected into the uterus to expand the cavity, allowing for clearer visualization of the uterine lining and any distorting submucosal fibroids.
A hysteroscopy, which involves inserting a thin, lighted scope through the cervix to directly view the inside of the uterus, may also be performed for definitive confirmation. Alongside imaging, a complete blood count (CBC) is often ordered to check for anemia, which helps quantify the impact of the blood loss. It is also important to rule out other structural or hormonal issues, such as polyps or thyroid disorders.
Targeting Bleeding with Treatment Options
Treatment for fibroid-related bleeding focuses on either managing the symptom medically or addressing the underlying tumor through procedural means. Initial medical management often involves hormonal contraceptives, such as oral pills or progestin-releasing intrauterine devices, to regulate cycles and reduce blood flow. Non-hormonal options like tranexamic acid can also be taken during the bleeding days to promote clotting and decrease the volume of flow.
For patients whose bleeding does not respond to medication, or who wish for a more definitive solution, minimally invasive procedures are available. Uterine Fibroid Embolization (UFE) is a non-surgical option where tiny particles are injected into the arteries supplying the fibroids to cut off their blood supply. This causes them to shrink and significantly reduces bleeding. Endometrial ablation is another technique that destroys or removes the uterine lining, which can be effective for smaller fibroids, though it is not suitable for women who desire future pregnancy.
Surgical options are often highly effective and are chosen based on the fibroid location and the patient’s desire to preserve fertility. A hysteroscopic myomectomy is a minimally invasive procedure performed through the cervix to remove submucosal fibroids. For larger or more numerous fibroids, a laparoscopic or open myomectomy removes the tumors while keeping the uterus intact. The complete surgical removal of the uterus, known as a hysterectomy, offers a permanent cure but is reserved for women who have completed childbearing.