Uterine polyps are soft, fleshy overgrowths of tissue that form on the inner lining of the uterus, known as the endometrium. Also called endometrial polyps, these growths range in size from a few millimeters to several centimeters and may be attached by a slender stalk or a broad base. While most uterine polyps are benign, or noncancerous, their presence can disrupt the normal function of the uterine lining. Abnormal vaginal bleeding is the most common sign, often prompting a person to seek medical evaluation.
Mechanism of Abnormal Uterine Bleeding
Uterine polyps frequently cause bleeding because their structure differs from the surrounding healthy endometrial tissue. These growths are highly vascularized, meaning they contain numerous small, fragile blood vessels. The surface layer covering the polyp is often thin and easily damaged, making it prone to breakdown and subsequent bleeding.
Abnormal bleeding can be triggered by mechanical irritation. A polyp suspended by a stalk may move or “dangle” within the uterine cavity, rubbing against the uterine wall. This friction can erode the fragile surface layer, exposing underlying blood vessels and leading to spotting or intermenstrual bleeding.
Polyps also react to hormonal changes throughout the menstrual cycle. They are sensitive to estrogen, which encourages the growth of the uterine lining, causing their enlargement. This growth can lead to congestion and localized breakdown within the polyp’s supporting tissue, resulting in the release of blood.
The types of bleeding associated with polyps are varied. Polyps can cause:
- Intermenstrual bleeding, which is spotting or bleeding that occurs between regular periods.
- Menorrhagia, characterized by unusually heavy or prolonged menstrual periods.
- Post-coital bleeding, due to mechanical trauma to the polyp during sexual activity.
- Any vaginal bleeding occurring after menopause, which is considered abnormal and frequently linked to polyps.
Recognizing Other Common Symptoms
While abnormal bleeding is the most frequent sign, uterine polyps can cause other noticeable symptoms. Some individuals may experience pelvic discomfort or cramping, especially if the polyps are large or have prolapsed through the cervix into the vaginal canal. This discomfort is typically mild but can be persistent.
An unusual or persistent vaginal discharge may also accompany uterine polyps. This discharge is sometimes described as white or clear and occurs due to inflammation or irritation caused by the abnormal growth within the uterine cavity.
Uterine polyps have an association with reproductive health and fertility. They may present a physical obstacle that interferes with the ability to conceive, possibly by blocking the fallopian tubes or impeding sperm movement. A polyp may also prevent a fertilized egg from implanting properly in the uterine wall, contributing to difficulty achieving pregnancy or recurrent miscarriage.
Diagnosis and Treatment Methods
Diagnosis usually begins with a transvaginal ultrasound, which uses sound waves to visualize the uterine lining and detect abnormal growths. To improve the clarity of the image, sonohysterography may be performed, where sterile saline fluid is injected into the uterine cavity to gently expand it, offering a clearer view of the polyps.
The definitive method for both diagnosis and treatment is often hysteroscopy. This minimally invasive procedure involves inserting a thin, lighted instrument with a camera through the vagina and cervix into the uterus to visually examine the entire cavity. If a polyp is identified, the hysteroscopy enables the immediate performance of a polypectomy, which is the surgical removal of the growth.
After removal, the polyp tissue is sent for a biopsy to rule out malignancy. While the vast majority of uterine polyps are benign, tissue analysis is important because about 5% may contain precancerous or cancerous cells. For small, asymptomatic polyps, particularly in pre-menopausal individuals, active monitoring may be suggested, as some small polyps may resolve on their own.