Endometrial polyps are common benign growths arising from the endometrium, the tissue lining the uterine cavity. These overgrowths are typically attached to the uterine wall by a thin stalk or a broad base and can range in size from a few millimeters to several centimeters. While many people with endometrial polyps experience no symptoms, the most frequent sign is Abnormal Uterine Bleeding (AUB). This bleeding can manifest as spotting between menstrual cycles, unusually heavy periods, or vaginal bleeding after menopause.
Spontaneous Resolution and Natural Course
The natural course of endometrial polyps is variable, making the question of spontaneous resolution complex. For many polyps, especially those that are small and asymptomatic, a “watchful waiting” approach may be appropriate, particularly in premenopausal individuals. Research suggests that spontaneous regression can occur, with reported resolution rates varying widely, often estimated between 6% and 25% over time.
The likelihood of a polyp resolving without intervention is strongly influenced by specific factors. Polyps generally less than two centimeters show a greater tendency to regress naturally. Spontaneous resolution is also observed much more frequently in premenopausal individuals who still have regular menstrual cycles. In contrast, polyps found in postmenopausal individuals rarely disappear and are typically persistent.
When a polyp is asymptomatic and small, conservative management involves periodic monitoring, usually with ultrasound, to check for changes in size. This approach avoids unnecessary surgical risk while allowing for natural resolution. However, if a polyp is causing symptoms like AUB, or if there is any suspicion of precancerous changes, monitoring alone is not recommended.
Hormonal Drivers and Who is at Risk
Endometrial polyps are fundamentally hyperplastic lesions, meaning they result from an overgrowth of the endometrial lining due to hormonal stimulation. The primary driver is the hormone estrogen, as polyp cells have a higher concentration of estrogen receptors compared to healthy tissue. This leads to a localized, exaggerated response to circulating estrogen, causing excessive tissue proliferation.
This imbalance often occurs when the endometrium is stimulated by estrogen without sufficient opposition from progesterone, which normally balances estrogen’s effects during the menstrual cycle. This hormonal environment explains why people approaching or past menopause face a higher risk, as fluctuating or unopposed estrogen levels are common. Increased endogenous estrogen production associated with obesity also elevates the risk, since fat tissue contains aromatase, an enzyme that converts androgens into estrogen.
Several other factors are consistently associated with an increased predisposition to developing endometrial polyps. These include hypertension (high blood pressure) and the use of certain medications. Specifically, the breast cancer drug Tamoxifen is a recognized risk factor because it acts as an estrogen agonist in the uterus, promoting endometrial cell growth.
Detection and Treatment Pathways
The initial step in identifying endometrial polyps typically involves a Transvaginal Ultrasound (TVS), which uses sound waves to create images of the uterus and its lining. While TVS is an effective first-line screening tool, its accuracy is limited in distinguishing a polyp from general endometrial thickening. For a more definitive diagnosis, Saline Infusion Sonohysterography (SIS), also called a hysterosonogram, is often performed. This specialized ultrasound involves injecting sterile saline into the uterine cavity, which expands the space and allows for a clearer outline of the polyp against the fluid.
The most accurate method for both diagnosis and treatment is Hysteroscopy, which is considered the gold standard procedure. This involves inserting a thin, lighted telescope-like instrument through the cervix to allow the physician to directly visualize the entire uterine cavity. Hysteroscopy provides precise information about the polyp’s size, location, and attachment, which is essential for determining the best course of action.
For polyps that are symptomatic, large, or found in high-risk patients, the standard treatment is surgical removal via Hysteroscopic Polypectomy. This procedure utilizes the hysteroscope to guide specialized instruments, such as small scissors, graspers, or a morcellator, to excise the polyp completely. Unlike simply scraping the uterine lining, hysteroscopic polypectomy ensures the entire base of the polyp is removed, which significantly reduces the risk of recurrence.
Every polyp that is surgically removed must be sent to a pathology laboratory for histopathological examination. This is a crucial step to confirm the growth is benign and to rule out the possibility of malignant or precancerous cells, which occur in an estimated 3% of cases. While hormonal medications may temporarily manage associated AUB symptoms, they are generally not an effective stand-alone treatment for shrinking existing polyps.