Uterine fibroids, also known as leiomyomas, are non-cancerous growths that develop from the muscle tissue of the uterus. They are extremely common, affecting a large percentage of women during their reproductive years, though many remain unaware they have them. While most fibroids do not cause symptoms, their location determines their impact on a woman’s health. Submucosal fibroids represent a specific, highly symptomatic subtype defined by their position within the uterine cavity. They often interfere directly with the reproductive system’s function, making them a significant concern.
Location and Structure of Submucosal Fibroids
Submucosal fibroids are distinct because they originate immediately beneath the endometrium, the inner lining of the uterus. This location means they project into the uterine cavity, often distorting its shape or size. In contrast, intramural fibroids grow within the muscular wall, and subserosal fibroids grow on the outer surface of the uterus.
The International Federation of Gynecology and Obstetrics (FIGO) classification system helps distinguish the extent of a submucosal fibroid’s intrusion. Type 0 fibroids are entirely within the uterine cavity, attached only by a stalk, making them pedunculated. Type 1 and Type 2 fibroids are partially embedded in the uterine wall. Type 1 has less than 50% of its volume within the wall, and Type 2 has 50% or more embedded.
Distinctive Symptoms and Reproductive Impact
The primary symptom associated with submucosal fibroids is abnormal uterine bleeding (AUB), particularly heavy and prolonged menstrual periods, a condition known as menorrhagia. The fibroid’s presence near the lining interferes with the normal process of endometrial sloughing and clotting, leading to excessive blood loss. This chronic bleeding can result in severe anemia, causing symptoms like persistent fatigue, dizziness, and weakness.
The abnormal tissue growth also causes intermenstrual bleeding or spotting between periods, which further contributes to blood loss. Because the fibroids physically alter the uterine cavity, they can significantly impact fertility and pregnancy outcomes. They may hinder the implantation of a fertilized egg into the uterine wall, leading to difficulty conceiving.
In established pregnancies, submucosal fibroids are associated with an increased risk of complications, including recurrent miscarriage. The fibroid may physically compete for space or interfere with the blood supply necessary for a developing fetus.
Diagnostic Procedures
Diagnosing submucosal fibroids often begins with a standard transvaginal ultrasound, which uses sound waves to create images of the uterus. While a traditional ultrasound can detect fibroids, specialized imaging is necessary to precisely determine the submucosal location and extent of cavity involvement. The most effective tool for this is Saline Infusion Sonohysterography (SIS).
During SIS, a sterile saline solution is gently introduced into the uterine cavity. This expands the space and provides a clearer contrast between the fibroid and the surrounding wall, allowing providers to accurately classify the fibroid according to the FIGO system. Hysteroscopy, a procedure where a thin, lighted scope is inserted through the cervix, offers direct visual confirmation and assessment of the fibroid’s size and attachment. Magnetic Resonance Imaging (MRI) is sometimes used as a secondary tool to map the overall size and location of all fibroids present.
Targeted Management and Treatment Options
Treatment for submucosal fibroids is often centered on symptom relief and removal. Medical therapies can be utilized to control bleeding in the short term. These options include hormonal treatments like GnRH agonists, which can temporarily shrink the fibroid and reduce blood flow, or non-hormonal medications such as tranexamic acid, which helps with clotting during heavy bleeding days.
The definitive treatment for most symptomatic submucosal fibroids is surgical removal, with Hysteroscopic Myomectomy being the preferred, minimally invasive method. This procedure involves inserting a specialized instrument through the cervix and vagina into the uterine cavity, where the fibroid is then shaved or resected. Because this approach avoids abdominal incisions and targets the fibroid directly, it allows for faster recovery and is favored for preserving the uterus for future fertility. For very large or complex fibroids, or when fertility is not a concern, options like Uterine Artery Embolization, traditional abdominal myomectomy, or hysterectomy may be considered.