Endometrial polyps are common growths originating in the lining of the uterus. The vast majority of these growths are benign, meaning they are non-cancerous. Understanding what they are, how they manifest, and the management options available can help prepare you for the next steps with your healthcare provider.
Defining Benign Endometrial Polyps
A benign endometrial polyp is a localized overgrowth of the endometrium, the tissue lining the inside of the uterus. These growths consist of endometrial glands, connective tissue (stroma), and a central vascular core. They can appear as small, bulbous protrusions or as finger-like projections, attaching to the uterine wall by either a thin stalk (pedunculated) or a broad base (sessile).
The size of these polyps is highly variable, ranging from a few millimeters to several centimeters, potentially filling the entire uterine cavity. While the term “benign” confirms the cells are non-cancerous, a small fraction—estimated to be between 0.5% and 4.8%—may harbor pre-cancerous cells or malignancy. This potential risk is why obtaining a tissue sample is important.
The development of these polyps is associated with hormonal influences, particularly high or unopposed estrogen levels. This explains why polyps are most frequently observed in individuals who are perimenopausal or postmenopausal, though they can occur at any age. Other factors that increase the likelihood of developing polyps include obesity, high blood pressure, and the use of certain medications like tamoxifen.
Recognizing Common Symptoms
Endometrial polyps often do not cause noticeable symptoms and are frequently discovered incidentally during routine imaging. When symptoms do occur, they are primarily related to abnormal uterine bleeding (AUB). This bleeding results from fragile blood vessels on the polyp’s surface or from the polyp interfering with the normal shedding of the endometrial lining.
The most frequently reported symptom is intermenstrual bleeding, which is spotting or bleeding between regular periods. Other manifestations include unusually heavy menstrual flow (menorrhagia) or periods that are irregular in timing and duration. For postmenopausal individuals, any vaginal bleeding or spotting is considered abnormal and is a common sign of an endometrial polyp.
Polyps can also be a factor in unexplained infertility or recurrent miscarriage, as they may interfere with the implantation of a fertilized egg. Some individuals may experience a watery or bloody vaginal discharge. These symptoms are not exclusive to polyps and warrant a full medical evaluation to determine the underlying cause.
Detection and Confirmatory Procedures
The initial step in identifying a potential endometrial polyp is typically a transvaginal ultrasound (TVUS). This procedure involves inserting a specialized probe into the vagina to create images of the uterus and its lining. On TVUS, a polyp often appears as a localized area of thickened endometrium or a hyperechoic mass within the uterine cavity.
To enhance diagnostic accuracy, especially when TVUS results are inconclusive, Saline Infusion Sonography (SIS), or a sonohysterogram, may be performed. This procedure uses a small catheter to fill the uterine cavity with sterile saline solution. The fluid expands the cavity, effectively outlining the polyp against the fluid and making it clearly visible. SIS is highly sensitive, often revealing small polyps missed by standard ultrasound, and can sometimes show the characteristic single blood vessel feeding the growth.
The gold standard for confirming the diagnosis and providing a definitive treatment pathway is hysteroscopy. A hysteroscope, a thin, lighted tube with a camera, is inserted through the vagina and cervix directly into the uterus. This allows the physician to visually inspect the polyp, assess its size and location, and perform a biopsy or immediate removal. Histological analysis of the tissue sample confirms the benign nature of the growth and rules out pre-cancerous or malignant cells.
Treatment and Long-Term Outlook
The management of a benign endometrial polyp depends on several factors, including symptoms, menopausal status, and the size of the growth. For small polyps (typically less than 10 millimeters) in premenopausal women who have no symptoms, expectant management may be chosen. This involves periodic monitoring, as up to 25% of small polyps may regress spontaneously over time.
Surgical removal, known as a polypectomy, is the recommended treatment for most polyps, especially those causing abnormal bleeding, infertility, or any polyp found in a postmenopausal patient. Hysteroscopic polypectomy is a minimally invasive procedure performed under direct visualization. The surgeon inserts the hysteroscope and uses specialized instruments (such as graspers, a resectoscope, or a morcellator) to precisely cut the polyp from the uterine wall.
Removing the polyp is highly effective at resolving symptoms like abnormal bleeding and can significantly improve fertility rates. The excised tissue is always sent for pathological examination to confirm its benign status. While the procedure is definitive, there is a risk of recurrence, generally reported between 2.5% and 15%. Factors such as having multiple polyps or chronic endometritis may increase the likelihood of new polyps forming, requiring follow-up care.