Endometrial polyps are benign localized lesions of the endometrium, which are commonly seen in women of reproductive age. Some may be precancerous or cancerous. They usually occur in women in their 40s and are rare in women under 20 years of age.

The main difference between uterine polyps and uterine fibroids is that fibroids are composed of muscle tissue and polyps are made of endometrial tissue.

No definitive cause of endometrial polyps is known, but they appear to be affected by hormone levels and grow in response to circulating estrogen. Risk factors include obesity, high blood pressure and a history of cervical polyps. Taking tamoxifen or hormone replacement therapy can also increase the risk of uterine polyps.

Endometrial polyps can be solitary or occur with others. They are round or oval and measure between a few millimeters and several centimeters in diameter. They are usually the same red/brown color of the surrounding endometrium although large ones can appear to be a darker red. The polyps consist of dense, fibrous tissue (stroma), blood vessels and gland like spaces lined with endometrial epithelium. If they are pedunculated, they are attached by a thin stalk (pedicle). If they are sessile, they are connected by a flat base to the uterine wall. Pedunculated polyps are more common than sessile ones.

Endometrial polyps can be detected by vaginal ultrasound (sonohysterography), hysteroscopy and dilation and curettage. Detection by ultrasonography can be difficult, particularly when there is endometrial hyperplasia (excessive thickening of the endometrium).
Although treatments such as hysteroscopy usually cure the polyp concerned, recurrence of endometrial polyps is frequent. Untreated, small polyps may regress on their own.

Associated disease

  • infertility
  • uterine polyps can be associated with malignancy (particularly in older, postmenopausal women)

Complications

Endometrial polyps are usually benign although some may be precancerous or cancerous. About 0.5% of endometrial polyps contain adenocarcinoma cells.

Risk factors

  • being perimenopausal or postmenopausal
  • high blood pressure (hypertension)
  • obesity
  • taking tamoxifen, a drug therapy for breast cancer
  • history of cervical polyps

It is believed that endometrial polyps may have an adverse effect on fertility and fertility treatment outcome.
The specific reason that polyps affect fertility is unknown, but polyps may create an inflammatory reaction inside the uterine cavity or cause irregular bleeding at the time of implantation. These effects would create a hostile environment for the implanting embryo and possibly prevent pregnancy or potentially cause miscarriages.

There is no way to prevent uterine polyps but endometrial resection proved effective in preventing their recurrence.

They often cause no symptoms. Where they occur, symptoms include irregular menstrual bleeding, bleeding between menstrual periods, excessively heavy menstrual bleeding (menorrhagia), and vaginal bleeding after menopause. Bleeding from the blood vessels of the polyp contributes to an increase of blood loss during menstruation and blood "spotting" between menstrual periods, or after menopause. If the polyp protrudes through the cervix into the vagina, pain (dysmenorrhea) may result.

Alternative therapies such as naturopathic medicine may help in shrinking the size of polyps.

Pharmacotherapy

Certain hormonal medications, including progestins and gonadotropin-releasing hormone agonists, may lessen symptoms of the polyp.
Surgical therapy

Endometrial polyps can be surgically removed  using curettage with (polypectomyor without hysteroscopy. When curettage is performed without hysteroscopy, polyps may be missed. To reduce this risk, the uterus can be first explored using grasping forceps at the beginning of the curettage procedure. Hysteroscopy involves visualising the endometrium (inner lining of the uterus) and polyp with a camera inserted through the cervix. If it is a large polyp, it can be cut into sections before each section is removed. If cancerous cells are discovered, a hysterectomy (surgical removal of the uterus) may be performed. A hysterectomy would usually not be considered if cancer has been ruled out. Whichever method is used, polyps are usually treated under general anesthetic.

However, surgical resection of endometrial polyps is recommended in infertile patients prior to treatment in order to increase natural conception or assisted reproductive pregnancy rates. 

Polyps can increase the risk of miscarriage in women undergoing IVF treatment. If they develop near the fallopian tubes, they may lead to difficulty in becoming pregnant. There is mixed evidence regarding the resection of newly diagnosed endometrial polyps during ovarian stimulation to improve the outcomes of fresh in vitro fertilization cycles.


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Sources

Endometrial polyp ―sourced from Wikipedia licensed under CC BY-SA 3.0
Endometrial polyp ―sourced from World Heritage Encyclopedia licensed under CC BY-SA 3.0
Endometrial polyp ―by Nephron licensed under CC BY-SA 3.0
Endometrial polyp ―by BruceBlaus licensed under CC BY-SA 4.0
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