Uterine fibroids are common, non-cancerous growths that develop within or on the muscular walls of the uterus. Also known as leiomyomas or myomas, these growths affect a large percentage of women during their reproductive years, though many remain asymptomatic. For women who experience symptoms, fibroids can cause constipation by exerting physical pressure on nearby pelvic structures.
The Physical Mechanism of Constipation
The primary cause of fibroid-related constipation is mechanical compression, which occurs as the growths increase in size. The uterus is situated in the pelvic cavity, closely surrounded by organs like the rectum and a portion of the large intestine. As a fibroid enlarges, it acts as a mass that pushes on these adjacent bowel structures.
This physical pressure on the colon or rectum restricts the internal channel, or lumen, of the bowel. This compression makes it difficult for stool to pass, slowing the transit time of waste material. This physical narrowing leads to typical signs of constipation, such as infrequent bowel movements, straining during defecation, and a sensation of incomplete bowel evacuation.
Some research suggests a less direct hormonal influence on bowel function. Fibroids are sensitive to estrogen, and the hormonal environment that promotes their growth may affect gastrointestinal motility. Elevated estrogen levels can sometimes slow peristalsis, the wave-like muscular contractions that move contents through the digestive system. However, the direct physical mass effect of the fibroid remains the most significant connection.
Location Dictates Symptoms
Not all fibroids cause constipation; the likelihood depends heavily on the growth’s location within the pelvis. Fibroids that grow on the outer surface of the uterus, known as subserosal fibroids, are particularly prone to causing bowel issues if they project backward. Large subserosal fibroids extending toward the back of the pelvis, near the rectum, are the most likely culprits for compression-related constipation.
This precise positioning near the rectum creates the obstructive pressure that impedes normal bowel function. Conversely, fibroids growing within the uterine wall (intramural fibroids) or into the uterine cavity (submucosal fibroids) are less likely to directly compress the bowel. While these types may cause other symptoms, such as heavy menstrual bleeding, their location often spares the digestive tract from mechanical interference.
Associated Gastrointestinal and Pelvic Symptoms
Constipation caused by uterine fibroids is frequently part of a broader cluster of gastrointestinal and pelvic symptoms. Many women report chronic bloating and a persistent feeling of abdominal fullness, which arises from the sheer mass of an enlarged uterus.
Digestive discomfort may also include pain during bowel movements or vague lower abdominal discomfort. Beyond the digestive system, fibroid pressure can affect the urinary tract. If fibroids are located toward the front of the uterus, they may press on the bladder, causing frequent urination or the inability to completely empty the bladder. This overall feeling of pelvic heaviness and pressure is a common complaint indicating significant internal growths.
When to Seek Medical Attention
Consult a healthcare provider if you experience chronic constipation that does not respond to standard lifestyle changes like increased fiber and hydration. Persistent or severe pelvic pain, especially if sharp and sudden, requires prompt medical evaluation. Any significant change in bowel habits or unexplained weight loss should also be reported immediately.
A physician will typically begin the diagnostic process with a comprehensive pelvic exam, during which they may feel a firm or irregular mass suggesting the presence of fibroids. To confirm the diagnosis and determine the size and exact location of the growths, imaging tests such as an ultrasound or a magnetic resonance imaging (MRI) scan are usually ordered. Management options range from watchful waiting for mild symptoms to medication or procedural intervention for severe cases. Addressing the underlying fibroids is the most effective way to achieve lasting relief from related constipation.