Uterine Polyps: Symptoms, Types, Causes and Treatment

Uterine polyps are a common gynecological condition that can impact women of all ages, though they are more frequently diagnosed in those of reproductive or perimenopausal age. While often benign, these growths can disrupt quality of life through symptoms such as abnormal uterine bleeding and fertility challenges. Understanding the symptoms, types, causes, and available treatments for uterine polyps is essential for informed decision-making and maintaining reproductive health. Let's explore the current evidence and insights from recent research.

Symptoms of Uterine Polyps

Uterine polyps, also known as endometrial polyps, may present with a range of symptoms—or none at all. Some women discover their polyps during routine exams, while others seek medical attention due to troubling signs. Being aware of these symptoms can prompt timely diagnosis and intervention, improving outcomes and quality of life.

Symptom	Description	Frequency/Note	Source(s)
Abnormal Bleeding	Includes heavy, irregular, or intermenstrual bleeding	Most common symptom	1 3 4 9 13
Infertility	Difficulty achieving pregnancy	Noted in a subset of women	1 2 4 5 8 10
Spotting/Discharge	Bleeding between periods or vaginal discharge	Associated with cervical polyps	1 3
Menstrual Disturbance	Changes in cycle regularity or volume	Present in a proportion of cases	4 13
Asymptomatic	No symptoms, detected incidentally	Significant portion	3 4

Table 1: Key Symptoms

Understanding the Symptom Spectrum

Abnormal Uterine Bleeding (AUB)

Abnormal uterine bleeding is by far the most common presenting symptom of uterine polyps. This can manifest as heavy menstrual bleeding (menorrhagia), irregular cycles, or bleeding between periods (intermenstrual bleeding). Polyps located in the uterine cavity are most often linked to AUB, while those in the cervical canal may cause more subtle spotting or discharge 1 3 4 9 13.

Infertility and Subfertility

Many women with uterine polyps experience difficulties with conception. Research suggests that polyps may interfere with embryo implantation or create an inhospitable uterine environment, potentially through molecular disruptions in endometrial receptivity 2 4 5 8 10. However, not all women with polyps face fertility challenges.

Spotting, Discharge, and Menstrual Disturbance

Spotting and non-menstrual discharge can also be a sign of cervical or small cavity polyps. Some women note a change in their regular menstrual patterns, such as more frequent or unpredictable cycles 1 4 13.

Asymptomatic Polyps

Interestingly, many polyps are discovered incidentally during routine pelvic exams or imaging for unrelated issues. Up to 60% of women in some studies reported no symptoms at all 3 4.

Types of Uterine Polyps

Uterine polyps are not a uniform entity. They vary in size, structure, and cellular makeup, each with distinct clinical implications. Understanding these differences can help guide diagnosis, management, and prognosis.

Type	Cellular Features / Origin	Frequency/Prevalence	Source(s)
Glandular	Composed mainly of endometrial glands	Most common (up to 79%)	4
Glandular-Cystic	Glands with cystic spaces	~35% of glandular polyps	4
Glandular-Fibrous	Mix of glands and fibrous stroma	~44% of glandular polyps	4
Fibrous	Mainly fibrous (connective) tissue	Less common (~13%)	4
Micro-Polyps	Small, less than 1 cm, often multiple	~8%	4
Adenomyomatous	Contains glands and smooth muscle (myomatous stroma)	May mimic more aggressive lesions	6

Table 2: Types of Uterine Polyps

Exploring the Different Types

Glandular and Glandular-Subtype Polyps

Most polyps are predominantly glandular, reflecting an overgrowth of the endometrial lining. These may further subdivide into glandular-cystic and glandular-fibrous types, depending on the presence of cystic spaces or fibrous tissue 4.

Fibrous Polyps and Micro-Polyps

Fibrous polyps are mainly made up of connective tissue. Micro-polyps are tiny, often found in clusters, and may be associated with endometrial hyperplasia 4.

Adenomyomatous Polyps

Adenomyomatous (polypoid adenomyomas) polyps are unique in that they contain both endometrial glands and smooth muscle tissue. These can be mistaken for more serious conditions such as adenosarcoma but are generally benign 6.

Location Matters

Polyps may arise in the uterine cavity, at the uterine cornu (cornual polyps), or in the cervical canal. Their location can influence both symptoms and management strategies. For example, smaller polyps (<1 cm) are more likely to be found in the cervical canal, while larger ones tend to be located within the uterine cavity 1.

Causes of Uterine Polyps

The precise causes of uterine polyps remain incompletely understood, though research is shedding light on the biological and environmental factors that contribute to their formation. Both local uterine changes and systemic influences play a role.

Factor	Description/Mechanism	Evidence/Notes	Source(s)
Hormonal Imbalance	Estrogen-dependent growth, unopposed estrogen	Major driver	4 7
Chronic Inflammation	Chronic endometritis, inflammatory markers	CD138 positivity, common	4
Genetic Changes	Somatic mutations in endometrial tissue	Cancer driver mutations	5 8
Oxidative Stress	High Cu/Zn ratio, low zinc	Suggested role	7
Environmental	Exposure to metalloestrogens (heavy metals)	Unclear, conflicting data	7
Age & Menopausal Status	More common in perimenopausal/postmenopausal women	Age-related changes	3 5

Table 3: Causes and Risk Factors

Delving into the Causes

Hormonal Imbalance

Uterine polyps are considered estrogen-dependent lesions. Prolonged exposure to unopposed estrogen—whether endogenous or exogenous—can stimulate the endometrial lining, leading to overgrowth and polyp formation 4 7. This helps explain their prevalence in perimenopausal and postmenopausal women.

Inflammation and Chronic Endometritis

Chronic, low-grade inflammation of the endometrium (chronic endometritis) is increasingly recognized as a key factor. Up to 43% of polyps show immunohistochemical markers (CD138 positivity) of chronic inflammation, suggesting an inflammatory basis for their development 4.

Genetic and Molecular Abnormalities

Recent genomic studies have revealed that polyps may harbor somatic mutations in genes known to drive endometrial cancer, albeit at low frequencies. These mutations are typically found in the epithelial cells of polyps, indicating a potential link between polyps and cancer risk, especially with advancing age 5 8. Additionally, transcriptomic analyses highlight disruptions in pathways such as Wnt signaling and vascular smooth muscle regulation, which may promote unrestrained tissue growth 8.

Oxidative Stress and Environmental Exposures

Oxidative stress, reflected by an elevated copper-to-zinc (Cu/Zn) ratio, may also be involved in the pathogenesis of polyps. However, the direct impact of heavy metal exposure (metalloestrogens) remains unproven 7.

Age and Other Risk Factors

Polyps are more likely to occur in women approaching or after menopause, possibly due to cumulative hormonal and molecular changes over time 3 5.

Treatment of Uterine Polyps

Management of uterine polyps is tailored to each woman's symptoms, reproductive goals, and risk factors. Advances in diagnostic and surgical techniques have expanded treatment options, making care more effective and patient-centered.

Treatment	Approach/Method	Effectiveness/Notes	Source(s)
Hysteroscopic Polypectomy	Minimally invasive, direct visualization	First-line, safe, effective	3 9 11 12 13
Outpatient Polypectomy	Polypectomy in office setting	Non-inferior to inpatient, cost-effective	13
Polypectomy + Ablation/Myomectomy	Combined with other procedures for complex cases	For coexisting pathologies	12
Hysterectomy	Removal of uterus	Reserved for recurrent/severe cases	12
Expectant Management	Observation for small/asymptomatic polyps	Some regress spontaneously	3
Blind D&C	Dilation and curettage without visualization	Low diagnostic accuracy, not recommended	9

Table 4: Treatment Approaches

Treatment Options and Outcomes

Hysteroscopic Polypectomy

Hysteroscopic removal of polyps is the gold standard. This minimally invasive procedure allows direct visualization and precise excision, ensuring high rates of symptom resolution and tissue retrieval for pathological assessment 3 9 11 12 13. Most women experience a significant reduction in abnormal bleeding and high satisfaction post-procedure 12 13.

Outpatient vs. Inpatient Polypectomy

Advancements now enable polypectomy in an outpatient setting. Recent trials show outpatient treatment is as effective as inpatient surgery, with similar rates of symptom improvement and quality of life, though there is a higher chance of incomplete removal and slightly reduced patient acceptability 13. Outpatient procedures are also more cost-effective for healthcare systems.

Combined and Surgical Options

In cases where polyps coexist with fibroids or other uterine abnormalities, polypectomy can be combined with endometrial ablation or myomectomy. Hysterectomy is reserved for women with recurrent, large, or suspicious lesions, or when malignancy cannot be ruled out 12.

Expectant Management

Small, asymptomatic polyps may resolve on their own, particularly in premenopausal women. Watchful waiting is an option if the risk of malignancy is low and symptoms are absent 3.

Ineffective or Outdated Approaches

Blind dilation and curettage (D&C) is no longer recommended due to low accuracy and the risk of missing polyps 9.

Fertility-Related Considerations

For women struggling with infertility, polypectomy can improve the chances of conception, especially before assisted reproductive techniques like intrauterine insemination (IUI) 10 11. The removal of polyps is linked to higher pregnancy rates in some studies.

Conclusion

Uterine polyps are a frequent, typically benign cause of abnormal uterine bleeding and can impact fertility in some women. Advances in diagnosis and minimally invasive treatment have improved outcomes and patient experience. Here’s a summary of the main points:

• Symptoms: Most commonly cause abnormal uterine bleeding, but may also lead to infertility, spotting, or remain asymptomatic.
• Types: Polyps vary by cellular makeup (glandular, fibrous, adenomyomatous) and location.
• Causes: Driven by hormonal imbalances, chronic inflammation, genetic changes, oxidative stress, and age-related factors.
• Treatment: Hysteroscopic polypectomy is first-line; outpatient treatment is increasingly favored for its effectiveness and convenience. Expectant management is an option for small, asymptomatic polyps.

Being proactive about symptoms and working with healthcare providers to choose the right management strategy is key to maintaining reproductive and overall health.