Uterine fibroids are non-cancerous growths that originate from the smooth muscle tissue of the uterus. These tumors are extremely common, affecting a significant portion of women by the time they reach menopause. Fibroids are classified based on their location within the uterine structure, which directly influences the kinds of symptoms they produce.
Understanding the Types of Uterine Fibroids
Fibroids are classified into three primary types based on their location within the uterine layers. The most common type is the intramural fibroid, which is embedded within the muscular wall of the uterus (myometrium). These fibroids can increase the overall size of the uterus and may cause heavy or prolonged bleeding.
Subserosal fibroids grow on the outer surface of the uterus, protruding into the pelvis. Because they grow outward, they typically cause “bulk symptoms” like pelvic pressure, frequent urination, or constipation if they press on adjacent organs, but they usually do not affect menstrual bleeding. Both intramural and subserosal fibroids can sometimes be attached to the uterus by a narrow stalk, known as pedunculated fibroids.
Submucosal fibroids are the least common type, yet they are the most likely to cause significant symptoms. These fibroids develop in the muscle layer immediately beneath the endometrium (the inner lining of the uterus). Their growth pattern involves projecting into the uterine cavity, and this specific positioning causes major health issues even when the fibroid is small.
Specific Symptoms Caused by Submucosal Growth
The unique location of submucosal fibroids, which distorts the lining of the uterine cavity, strongly associates them with severe symptoms. The most frequent and disruptive symptom is abnormal uterine bleeding (AUB), including menorrhagia (excessively heavy or prolonged periods) and intermenstrual bleeding. Menorrhagia often involves periods lasting more than seven days.
The fibroid’s presence beneath the endometrium disrupts the normal shedding and clotting process, leading to excessive flow. This chronic, heavy blood loss frequently results in anemia, characterized by a low red blood cell count. Symptoms of anemia, such as fatigue, dizziness, and weakness, often prompt patients to seek medical attention.
Submucosal fibroids also have a significant impact on reproductive health, making them the type most likely to cause fertility issues. By altering the smooth contour of the uterine cavity, they can interfere with the implantation of a fertilized egg, leading to difficulty conceiving. They are also linked to an increased risk of miscarriage and recurrent pregnancy loss because the distorted environment may not support a developing fetus.
Confirming the Diagnosis
Diagnosing submucosal fibroids requires specialized imaging techniques because standard pelvic ultrasound often provides insufficient detail of the uterine cavity. Transvaginal ultrasound (TVUS) is usually the initial step, offering a view of the uterus by placing the probe directly into the vagina. To clearly define the fibroid’s precise relationship to the inner lining, however, a more advanced procedure is necessary.
Saline Infusion Sonography (SIS) is a highly effective diagnostic tool. This procedure involves introducing a sterile saline solution into the uterine cavity through the cervix while performing a TVUS. The fluid distends the cavity, creating a contrast that allows a clear outline of the fibroid and helps determine how much of the fibroid projects into the cavity.
Hysteroscopy serves as both a diagnostic and therapeutic procedure. For diagnosis, a thin, lighted telescope is inserted through the cervix to directly visualize the uterine cavity and the fibroid. This direct view helps map the size and location of the submucosal growth, which is necessary for planning the most appropriate intervention.
Intervention and Removal Options
Treatment for submucosal fibroids primarily focuses on removing the growth to resolve symptoms and improve fertility potential. For fibroids that project significantly into the uterine cavity, Hysteroscopic Myomectomy is the preferred, first-line intervention. This is a minimally invasive surgical procedure performed entirely through the vagina and cervix, eliminating the need for abdominal incisions.
The surgeon uses a specialized instrument called a resectoscope or hysteroscope, which is equipped with a wire loop or electrosurgical tool, to carefully cut and remove the fibroid tissue from the uterine wall. This approach is ideal for submucosal fibroids because their position within the cavity makes them directly accessible. The procedure is often performed on an outpatient basis, offering a faster recovery time compared to abdominal surgery.
Prior to surgery, or for patients with less severe symptoms, medical therapy may be used to manage bleeding or reduce the size of the fibroid. Medications like Gonadotropin-releasing hormone (GnRH) agonists or antagonists can temporarily block hormone production, leading to a reduction in fibroid size and bleeding. For individuals who have completed childbearing and have extensive, recurrent, or very large fibroids that are not suitable for hysteroscopic removal, a hysterectomy—the surgical removal of the entire uterus—remains a definitive final option.