Uterine polyps, also known as endometrial polyps, are exaggerated formations of endometrial tissue placed in the uterus, mainly in the endometrium (inner layer of the uterus). The most common symptom derived from their presence is bleeding. Also, they may prevent a woman from getting pregnant. Although most of them are considered benign, some can be cancerous. They can be removed by means of surgical hysteroscopy, a simple procedure with a low likelihood for complications.
The various sections of this article are assembled in the following table of contents.
Definition and causes
Endometrial polyps may appear when part of the basal layer of the endometrial lining proliferates. When this occurs, the basal layer has no response to the hormonal changes that take place during the menstrual cycle or is shed with each menstrual period.
Polyps are not exclusively associated with the female reproductive system, but can grow in different parts of the body. In fact, the meaning of the noun polyp, according to the Merriam-Webster Dictionary, is as follows:
A growth projecting from a mucous membrane (as of the colon or vocal cords).
During menstruation, the outer layer of the endometrium, known as functional later, is shed. With polyps, the basal layer of the endometrium remains in the womb and continues to grow solitarily.
Although researchers have discovered certain mechanisms that can trigger the proliferation of uterine polyps, the truth is that the particular causes leading to their formation are still unknown. However, it is known that they tend to grow when the levels of estrogen are elevated.
Risk and protective factors
There are a number of factors that may increase the risk of developing an uterine polyp, including:
- Elevated estrogen levels
- Chronic anovulation, that is, when ovulation does not occur despite having menstrual cycles
- Luteal insufficiency: the corpus luteum does not produce enough progesterone
- Age: the risk increases with age, and their prevalence is higher in women aged between 45-65 years
- Tamoxifen use, drug used to treat breast cancer
- Chronic inflammation of the uterine lining
- Hormone therapies in post-menopausal patients
- Obesity and arterial hypertension
- Rare genetic diseases, including the Lynch syndrome (a.k.a. HNPCC) or the Cowden’s disease
One should note that having any of the above listed symptoms does not mean that you suffer from endometrial polyps—it just indicates that the chances of developing one are higher.
On the other hand, there exist also a series of protective factors that can reduce your chances of developing polyps in the uterus. For instance, hormonal contraception and pure progestogens, due to their antiestrogenic effect.
Types of endometrial polyps
We can classify uterine polyps into different groups according to their appearance and composition:
- Functional polyps
- Their aspect resembles a normal endometrium.
However, they can present changes at a proliferative or a secretive level.
Depending on the principal element of their composition (glandular or estromal component), we can subdivide them into glandular, fibroglandular, or fibrotic polyps.
- They emerge when gland polyps become cysts.
- Their changes similar to those that occur with endometrial hyperplasia. Hyperplastic endometrial polyps without atypia are benign, but those with atypia can mean cancer.
- They are commonly detected on menopausal patients.
- The cells of these polyps go through a malignification process and become cancerous.
Depending on how they look like on ultrasound, we can distinguish between two types of polyps:
- They can be described as flat growths.
- They have a stalk that makes them narrower.
Small polyps are usually asymptomatic and women do not even notice them. Fortunately, this happens in 50% of the patients.
However, when the polyp grows, its more characteristic symptom appears: a heavy bleeding during menstruation (hypermenorrhea).
Bleeding between menstruations (metrorrhagia) or even after sexual intercourse are also common symptoms. It is believed that 10-30% of the cases in which an irregular intermenstrual bleeding occurs are related to the presence of endometrial polyps. In fact, they are the main cause, especially during perimenopause.
Another symptom that women may present is anemia, due to the frequent and abundant hemorrhages produced by the polyps. Pain is a common symptom as well, and it is caused by the dilation of the cervix.
Polyps can also affect female fertility, as they are associated with experiencing trouble conceiving and inability to bear a pregnancy to term.
Infertility and pregnancy
The exact mechanism that causes these problem is still unknown. However, some experts suspect that the bleeding caused by polyps can affect endometrial growth. This translates into unfavorable environmental conditions for embryo implantation, thereby compromising endometrial receptivity.
It has also been observed that patients with polyps have higher levels of glycodelin, a protein that inhibits the union between the egg cell and the sperm cell. For this reason, polyps can hinder the fertilization process, too.
Between 15% and 24% of the women suffering sterility problems present polyps in their uterus. Small polyps of less than 2 cm do not reduce the pregnancy rate in IVF patients, but we know that they rise the rate of miscarriage. So, treating them to restore a normal uterine cavity is a key factor to succeeding in IVF and other fertility treatments.
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Uterine polyps and cancer risk
It should be clear that endometrial polyps are overgrowths of cells from the uterine lining, and for this reason they are considered to be tumors. The vast majority, however, are considered benign, without severe conditions associated. Less than 5% are cancerous.
The chances for an endometrial polyp to turn malignant are higher in postmenopausal women, or in those women who take tamoxifen or experience heavy and/or irregular menstrual periods.
Learn more about the relationship between uterine polyps and cancer in the following post: Can uterine polyps become cancerous?
Diagnosis and treatment
Polyps are generally found through routine gynecological examinations through a transvaginal ultrasound. However, to be sure about the diagnosis, the following tests might be required:
- Hysterosonogram (or hydrosonography)
- It involves a transvaginal ultrasound, but injecting a small amount of sterile saline into the uterine cavity to separate the walls of the uterus from each other to see the polyp more accurately.
- Minor outpatient surgery whereby an endoscope is inserted, along with a light source and a camera, into the uterine cavity. Thanks to the endoscope, which carries a surgical instrument, we can get a digital image of the uterus. Local anesthesia can be used optionally.
Hysteroscopy, which is the method of choice to confirm the diagnosis, allows the doctor to perform a biopsy or a resection of the polyp, or even remove it surgically (hysteroscopic polypectomy).
Another way of eliminating small-sized polyps is by scraping the uterine cavity. The procedure, which is known as dilation and curettage (D&C), is less effective than the ones mentioned above. Moreover, if the base of the polyp is not properly removed, they may recur, that is, grow back.
Irrespective of the treatment used, a small part of the polyp (after having been removed) is sent to the lab for its analysis, which will confirm whether it is a benign type of polyp.
Polypectomy is used to treat any type of endometrial polyp that comes along with symptoms. In fact, it is recommended to proceed to their removal when their length exceeds 1 cm, even if they are not accompanied by any symptoms, as they have greater chances of turning cancerous.
When the patient experiences heavy bleeding or very severe symptoms associated with polyps, fibroids, or if there is a high risk for endometrial cancer, endometrial ablation (EA) may be an option. Learn more about this technique here: What is uterine ablation?
Uterine polyps and IVF success
If you are about to begin a fertility treatment and have been detected a polyp, it is strongly recommended that you have it removed before getting started.
The good news for these patients is that polyps can usually be detected early, as typically IVF patients undergo firstly a transvaginal ultrasound. This allows the gynecologist to find it out in case it exists. If so, the patient would be referred to hysteroscopy immediately.
If polyps were diagnosed once the treatment is started, the way to proceed may vary on a case-by-case basis—scheduling the embryo transfer as anticipated, freezing the embryos for later use, cancel the cycle to remove the polyp, etc.
FAQs from users
How much does hysteroscopy for uterine polyp removal cost?
Normally, the cost of hysteroscopy ranges from $750 to $3,500, although it varies on a case-by-case basis. If the procedure includes surgery and/or general anesthesia, you can expect a price of up to $7,000 or over. In some cases, it can be partially covered by health insurance if it is considered medically necessary.
Do uterine polyps need to be removed?
No, some polyps do not require treatment if they do not cause any symptoms. Basically, they can be treated by means of medication or surgery, depending on each woman. If they cause heavy bleeding during menstruation, or if they are suspected to be pre-cancerous, they should be treated at once.
Can uterine polyps go away on their own?
Yes, some small polyps disappear or shrink on their own even if they are left untreated. If the patient presents no symptoms that complicate her normal lifestyle, polyps can be left alone and watched to see if they resolve by themselves. Sometimes, they are treated with medications that make polyps dissolve and disappear eventually.
Do uterine polyps cause cramps?
Yes, although this is not a common symptom. Cramping typically appears when a patient has a large endometrial polyp. Menstrual-like cramps occur when polyps are present because the womb is naturally “designed” to push out anything that it detects inside.
Do uterine polyps cause weight gain?
No, this symptom appears with fibroids, which are often confused with polyps, which is not the same. While polyps are abnormalities of the uterine lining made of endometrial tissue, fibroids are benign tumors of the uterus that are composed of muscle tissue. Fibroids can cause painful periods, pelvic pain, infertility, etc.
Do uterine polyps come back?
Yes, they sometimes regrow after treatment, either surgery or medications. When polyps return, additional treatment may be necessary, depending on the severity.
Although there is no way to prevent endometrial polyps, attending all regular gynecological checkups can help to reduce the chances for them to grow back after removal. Factors such as high blood pressure, obesity, or taking tamoxifen can increase a woman’s chances of developing uterine polyps.
How fast do uterine polyps grow back?
The truth is, the growth rate of uterine polyps is rather low. Only a small percentage of polyps seem to come back—and if they do so, it can happen months or even years after treatment. It should be noted that they are more likely to develop in women who are between 40 and 50 years old. They rarely appear in women in their 20s or 30s.
Can uterine polyps prevent pregnancy?
In the most severe cases, yes. When uterine polyps grow near the Fallopian tubes, they may obstruct the opening of the tubes and lead to difficulty with getting pregnant. Also, if they irritate the uterine lining, they can prevent embryo implantation.
Do uterine polyps go away after menopause?
There is no reason why. In fact, the development of polyps typically occurs in pre-menopausal, menopausal, and post-menopausal women, who are more prone to develop them than younger girls.
Where do uterine polyps come from?
From an overgrowth of cells in the uterine lining (endometrium). In other words, endometrial polyps gro from endometrial tissue that attaches to the endometrium. Unfortunately, the exact cause is not known yet.
Can uterine polyps rupture?
In some cases, uterine polyps that grow towards the cervix or are near to that area, known as cervical polyps, can burst if knocked during sexual intercourse. As a consequence, they will begin to bleed.
Can endometriosis cause uterine polyps?
Several scientific studies have shown that the risk of endometrial polyps increases in endometriosis patients. It should be noted that both are estrogen-dependent overgrowths of the endometrium, some it is only logical that they are associated with each other in some aspects. Moreover, this rate is believed to be slightly higher in women with stage 2 and stage 3 endometriosis compared with those at stage 1.
Can acupuncture help with uterine polyps?
Acupuncture, as well as other remedies such as Ayurveda and certain herbal treatments, are commonly believed to help with endometrial polyps. However, there is no scientific evidence of this and patients can turn to these treatments voluntarily.
It is often said that certain foods, such as ginger, cinnamon, or mustard seeds can make polyps disappear on their own. As a method for preventing their appearance, a balanced diet, rich in antioxidants, along with a healthy lifestyle can be beneficial, but there is no scientific evidence to date either.
The safest methods to deal with uterine polyps are the ones described through this article. Keeping in mind that polyps can turn into cancer, we do not recommend that you take unnecessary risks.
Suggested for you
As stated above, although most polyps are non-cancerous, some may become malignant, so it should be clear that the risk of developing cancer exists. Want to learn more about this type of polyps, too? If so, you can get further info here: Can Uterine Polyps Become Cancerous?
If you are interested in learning the differences between uterine polyps and myomas, we recommend that you visit the following link: What Are Myomas or Uterine Fibroids?