What are endometrial polyps?
Endometrial polyps, also called uterine polyps, are growths in the interior of the uterus (womb), formed of an overgrowth of the cells (endometrium) that line this cavity. They may occur alone or in clusters and are typically less than a centimeter in diameter, but in rare cases can grow much larger – for example, to the size of a golf ball or an orange.
Symptoms in adults, both pre- and postmenopausal, commonly include unusual bleeding. Polyps are more common in people who have not yet experienced menopause than those who have. This may be because endometrial polyps seem to be reactive to estrogen levels. However, much is unknown about the formation of these polyps. They rarely occur in adolescents. Endometrial polyps can affect a woman’s fertility and, in rare cases, be linked to cancer.
Uterine polyp symptoms
- Irregular menstrual bleeding: Menstrual bleeding that is shorter or longer in length than usual, or that occurs at unexpected times
- Spotting or bleeding between menstrual periods
- Unusually heavy bleeding during periods
- Unusual appearance of brown blood after a menstrual period
- Spotting or bleeding after menopause
- Spotting or bleeding after sexual intercourse
- Severe menstrual cramping, though this is uncommon
Many of these symptoms do not arise from the formation of the polyp itself, but because of rubbing and irritation of the surrounding tissue. Most endometrial polyps are small, and many people who experience them will never develop symptoms. Pain is not a typical symptom of uterine polyps.
Endometrial polyp causes
Endometrial polyps are caused by the overgrowth of endometrial tissue, which is the lining of the uterus that swells and then shrinks during the menstrual cycle. Endometrial polyps are estrogen-sensitive, with hormones in the bloodstream playing a role in their occurrence.
- Going through perimenopause
- Hormone replacement therapy after menopause, particularly where the dose of estrogen is high
- Treatment with the medication tamoxifen for breast cancer, after menopause
Diagnosis of endometrial polyps
Transvaginal ultrasound (TVUS) is the first-line method for evaluating women with abnormal vaginal bleeding. During a TVUS, a thin, wand-like device is placed inside the vagina and uterus, where it emits ultrasonic waves. The doctor may be able to identify a uterine polyp by examining this ultrasound.
If the ultrasound finding is uncertain, there are two other options. One is where the physician carries out a more specialized ultrasound, called a sonohysterography or a saline infusion sonogram (SIS). In this procedure, the doctor injects a small amount of saline into the uterus to expand the uterine cavity and provide a clearer picture.
The second option, should a TVUS be uncertain, is a hysteroscopy. This allows a more direct view of the inside of the uterus, using a hysteroscope: a lighted camera mounted on a flexible rod. The hysteroscope may be equipped with an additional tool to gather a biopsy sample. A suction catheter could also be used to gather an endometrial biopsy. The tissue sample will then be analyzed to see if it indicates uterine cancer.
Treatments for endometrial polyps
Small, asymptomatic polyps in people before menopause often require no treatment, but will instead be monitored for changes or an increase in symptoms.
A short-term option to address the symptoms of endometrial polyps is the use of hormonal treatments, such as gonadotropin-releasing hormone agonists and progestins. However, since symptoms usually recur once treatment is stopped, this is not the preferred long-term treatment option.
Uterine polyp removal, called polypectomy, which is carried out using a hysteroscopy, is the standard procedure. The doctor uses a camera attached to a long, thin tube to examine the interior of the uterus, locate the polyp and then remove it with an integrated wire loop or blade. It is typically screened for cancer.
The removal of small endometrial polyps using hysteroscopy can sometimes be done as an outpatient procedure at a doctor’s office, but removing large polyps may require a hospital stay. Many people are able to return to normal activities within the next few days. Side-effects of uterine polyp removal may include light spotting.
Preventing endometrial polyp recurrence
In most cases, endometrial polyps do not recur after they have been removed by polypectomy. If they do recur, a repeat polypectomy procedure may be recommended.
If a person is concerned, an intrauterine device (IUD) can be inserted into the uterus to help prevent a recurrence of uterine polyps. This contraceptive may be a good choice for those who hope to maintain their fertility. Endomyometrial resection (EMR) – the surgical removal of around 5 mm of the uterine lining and some underlying muscle tissue – is another option, though this is a complex procedure and may not be appropriate for everyone. It is typically only recommended for people who do not wish to have children.
Endometrial/uterine polyps and pregnancy
It is thought that endometrial polyps may have a negative impact on a person’s fertility, but further research is needed in this field. Many doctors recommend removing polyps if the person is undergoing evaluation for infertility or has a history of miscarriage. Nevertheless, studies do not suggest that endometrial polyps are associated with miscarriage.
If younger people who may wish to have children undergo polypectomy (surgery to remove the polyps), it must be ensured that the deep lining of the uterus is not damaged.
Uterine polyps FAQs
Q: Are uterine polyps related to cancer?
A: Roughly 95 percent of the time, endometrial polyps are benign (noncancerous), but in about five percent of cases they are linked to cancer. If uterine polyps can develop into cancer, they are called precancerous. Among people with endometrial polyps, those presenting with bleeding and those older than 50 are more likely to have cancerous endometrial polyps.
Q: How are endometrial polyps different from uterine fibroids (leiomyoma)?
A: Endometrial polyps are formed from the lining of the uterus and therefore only occur within the uterine cavity. Fibroids come from the uterine musculature and may arise on any part of the uterus interior, exterior or the uterine wall. Uterine polyps have roughly a five percent chance of being related to cancer (malignant), while fibroids have less than a one percent likelihood of malignancy.
“The management of endometrial polyps in the 21st century.” The Obstetrician & Gynecologist. 2012. Accessed: May 31, 2018 ↩
“Uterine Polyps Can Cause Infertility or Miscarriage.” Advanced Fertility Center of Chicago. Accessed: July 18, 2017 ↩
“Differentiating uterine leiomyomas (fibroids) from uterine sarcomas.” UpToDate. December 28, 2017. Accessed: May 31, 2018 ↩