Uterine fibroids are common, non-cancerous growths that develop in or on the uterus. Also known as leiomyomas or myomas, these muscular tumors vary in size, from as small as an apple seed to as large as a grapefruit. While many individuals with fibroids experience no symptoms, others may encounter discomfort, including side pain.
What Are Fibroids and Where Do They Grow?
Fibroids are composed of smooth muscle cells and fibrous tissue, forming within the wall of the uterus or on its surface. They are common, affecting up to 80% of women before age 50. Hormones like estrogen and progesterone, which regulate the uterine lining, appear to influence their growth.
Fibroids are categorized by their location. Intramural fibroids grow within the muscular wall of the uterus. Submucosal fibroids develop beneath the inner lining and can protrude into the uterine cavity. Subserosal fibroids grow on the outer surface, sometimes extending into the pelvic cavity. Pedunculated fibroids are attached to the uterus by a stalk-like structure, either on the outside or inside.
Mechanisms of Fibroid-Related Side Pain
Fibroids can cause side pain through several mechanisms, often related to their size, location, and any changes they undergo. Larger fibroids, especially subserosal ones, can exert pressure on nearby organs, nerves, or blood vessels in the pelvis. For example, a fibroid on the right side might press on the bladder or rectum, leading to discomfort perceived as side pain. If a fibroid is located towards the back, it can press on pelvic or sciatic nerves, causing pain to radiate down the legs or into the lower back.
Fibroid degeneration is another cause of acute pain, which can be felt in the side. This occurs when a fibroid outgrows its blood supply, leading to cell death. This process releases chemicals that can cause sharp, intense pain and swelling in the pelvic area, localized to the side where the degenerating fibroid is situated. This pain usually subsides within a few days to a few weeks, though it can recur if the fibroid continues to grow and degenerate.
Pedunculated fibroids can also cause sudden, sharp side pain if the stalk twists. This twisting, known as torsion, cuts off the fibroid’s blood supply, leading to acute pain. While rare, torsion is a medical emergency due to tissue damage risk. The pain may be severe, often requiring prompt medical attention.
Other Common Indicators of Fibroids
While side pain can be a symptom, fibroids frequently present with other indicators. Heavy menstrual bleeding is common, often leading to prolonged periods lasting seven days or more. This excessive bleeding can result in anemia, causing fatigue and weakness. Many individuals also report a feeling of fullness or pressure in the lower abdomen, sometimes with bloating or an enlarged uterus that can make the abdomen appear distended.
Fibroids can also affect bladder and bowel function. Pressure on the bladder can lead to frequent urination or difficulty completely emptying it. Similarly, pressure on the rectum may cause constipation or a sensation of rectal fullness. Pain during sexual intercourse is another symptom, particularly if fibroids are located near the cervix or cause uterine shape distortion.
When to Consult a Doctor
Seeking medical attention is advisable if you experience persistent or worsening side pain, especially if severe or acute. New or severe pelvic pain, unexplained changes in bladder or bowel habits, or heavy and prolonged menstrual bleeding that impacts daily life are also reasons to consult a healthcare provider. Any bleeding between periods or signs of anemia, such as ongoing tiredness and weakness, warrant medical evaluation.
While many fibroids are asymptomatic and do not require treatment, a proper diagnosis can help determine the cause of your symptoms and guide management. Medical professionals can conduct pelvic exams and imaging tests like ultrasound or MRI to confirm the presence, size, and location of fibroids. Discussing your symptoms with a doctor ensures personalized advice and care.