Uterine polyps are a common cause of abnormal vaginal bleeding. Most are harmless, but they can sometimes cause troublesome symptoms and, rarely, may contain abnormal or cancerous cells.
If you have bleeding between periods, unusually heavy periods or bleeding after the menopause, a uterine polyp may be one possible cause.
What is a uterine polyp?
A uterine polyp, also called an endometrial polyp, is a small growth that develops from the lining of the womb.
The lining of the womb is called the endometrium. Sometimes a small area of this lining grows more than usual and forms a soft lump that projects into the inside of the womb.
Polyps can be:
- very small or several centimetres in size
- single or multiple
- attached to the womb by a broad base or a thin stalk
They are sometimes described as looking like a small grape hanging inside the womb.
Most uterine polyps are benign, meaning they are not cancerous.
What symptoms can uterine polyps cause?
Some women with polyps have no symptoms at all. The polyp may only be discovered during an ultrasound scan or another investigation.
When symptoms do occur, abnormal bleeding is the most common problem.
Polyps may cause:
- bleeding between periods
- irregular periods
- heavier than usual periods
- periods that last longer than normal
- spotting
- bleeding after sex
- bleeding after the menopause
Bleeding between periods is particularly common with polyps.
Why do polyps cause bleeding?
Polyps contain small blood vessels.
Because they project into the womb cavity, these blood vessels can sometimes become fragile and bleed easily.
A polyp may also interfere with the normal way the lining of the womb grows and sheds during the menstrual cycle.
This can lead to unpredictable spotting, bleeding between periods or heavier menstrual bleeding.
Who can develop uterine polyps?
Polyps can occur at almost any adult age, but they become more common as women get older.
They can occur both:
- before the menopause
- after the menopause
Certain factors may make polyps more likely, including:
- increasing age
- obesity
- high blood pressure
- diabetes
- taking tamoxifen for breast cancer
- some forms of hormone treatment
Having one of these risk factors does not mean you will develop a polyp.
Are uterine polyps cancerous?
The great majority of uterine polyps are benign.
However, occasionally a polyp may contain:
- abnormal cells
- precancerous changes
- endometrial cancer
The risk is generally higher in women who are older or postmenopausal, particularly if they have vaginal bleeding.
This is why bleeding after the menopause should always be investigated.
How are uterine polyps diagnosed?
Ultrasound scan
A transvaginal ultrasound scan is often one of the first investigations.
During this scan, a small ultrasound probe is gently placed inside the vagina. This gives a clearer picture of the womb and its lining.
A polyp may appear as a small growth inside the womb.
However, an ultrasound cannot always tell the difference between a polyp and other conditions, such as a fibroid or thickening of the womb lining.
Hysteroscopy
A hysteroscopy allows the doctor or nurse to look directly inside the womb.
A very thin telescope with a camera is gently passed through the vagina and cervix into the womb.
This allows the healthcare professional to see whether a polyp is present.
One advantage of hysteroscopy is that a polyp can sometimes be diagnosed and removed during the same appointment. This is often called a “see and treat” hysteroscopy.
How are uterine polyps treated?
Treatment depends on:
- your symptoms
- your age
- whether you have gone through the menopause
- the size and appearance of the polyp
- your personal risk factors
- whether you are trying to become pregnant
Hysteroscopic polypectomy
If a polyp is causing bleeding, it is usually removed using hysteroscopy.
This procedure is called a hysteroscopic polypectomy.
The doctor can see the polyp directly and remove it using small instruments passed through the hysteroscope.
This is preferred to removing a polyp without seeing it directly because it allows the doctor to remove the polyp more accurately.
Many polyps can be removed during an outpatient appointment without needing a general anaesthetic.
What happens to the polyp after it is removed?
The tissue is usually sent to the laboratory for examination under a microscope.
This is known as histology.
The laboratory checks whether the polyp is:
- completely benign
- showing abnormal or precancerous changes
- very rarely, cancerous
Most results are reassuring.
Do all polyps need to be removed?
Not necessarily.
Small polyps in younger women who have no symptoms may sometimes disappear naturally.
Your doctor may recommend monitoring rather than immediate treatment if:
- you have no abnormal bleeding
- the polyp appears small and harmless
- you have no significant risk factors
However, removal is more likely to be recommended if:
- you have persistent bleeding between periods
- your periods are very heavy
- the polyp is large
- you are having fertility treatment
- the diagnosis is uncertain
- you have risk factors for womb cancer
- you have bleeding after the menopause
Polyps after the menopause
Bleeding after the menopause is not considered normal and should always be checked.
Although a polyp is often the cause and is usually benign, doctors need to make sure there is no more serious problem such as endometrial cancer.
If a polyp is found in a woman with postmenopausal bleeding, hysteroscopy and removal of the polyp for laboratory examination will often be recommended.
Can polyps affect fertility?
Sometimes.
A polyp inside the womb may interfere with the implantation of an embryo.
For this reason, doctors may recommend removing certain polyps in women who are having difficulty becoming pregnant or undergoing fertility treatment.
However, infertility can have many different causes, so finding a polyp does not necessarily mean it is the reason for difficulty conceiving.
When should you see a doctor?
Speak to a healthcare professional if you experience:
- repeated bleeding between periods
- periods that suddenly become much heavier
- irregular bleeding that continues
- bleeding after sex
- any vaginal bleeding after the menopause
There are many possible causes of abnormal bleeding, and most are not cancer.
However, persistent or unusual bleeding should always be investigated.
The key message
Uterine polyps are common growths that develop from the lining of the womb.
Most are harmless, but they can cause bleeding between periods, heavy periods or bleeding after the menopause.
An ultrasound scan may suggest a polyp, while hysteroscopy allows doctors to look directly inside the womb and, in many cases, remove the polyp at the same time.
Most removed polyps are benign, but they are usually examined in the laboratory to make sure there are no abnormal cells.
If you are experiencing new, persistent or unusual vaginal bleeding, particularly after the menopause, it is important to seek medical advice.
This article is based on information from the Royal College of Obstetricians and Gynaecologists (RCOG) and The Obstetrician & Gynaecologist (TOG). It is intended for general information and does not replace individual medical advice.