Fibroids are non-cancerous growths that develop in or around the womb (uterus).
The growths are made up of muscle and fibrous tissue and vary in size. They're sometimes known as uterine myomas or leiomyomas.
Many women are unaware they have fibroids because they don't have any symptoms. Women who do have symptoms (around one in three) may experience:
- heavy periods or painful periods
- tummy (abdominal) pain
- lower back pain
- a frequent need to urinate
- pain or discomfort during sex
Seeing your doctor
As fibroids don't often cause symptoms, they're sometimes diagnosed by chance during a routine gynaecological examination, test or scan.
However, see your doctor if you have persistent symptoms of fibroids so they can investigate possible causes.
If your doctor thinks you may have fibroids, they'll usually refer you for an ultrasound scan to confirm the diagnosis.
Read more about diagnosing fibroids .
Why fibroids develop
The exact cause of fibroids is unknown. However, they're linked to the hormone oestrogen. Oestrogen is the female reproductive hormone produced by the ovaries (the female reproductive organs).
Fibroids usually develop during a woman's reproductive years (from around 16 to 50 years of age) when oestrogen levels are at their highest. They tend to shrink when oestrogen levels are low, such as after the menopause (when a woman's monthly periods stop).
Who gets fibroids?
Fibroids are common, with around 1 in 3 women developing them at some point in their life. They most often occur in women aged 30-50.
Fibroids are thought to develop more frequently in women of African- Caribbean origin. It's also thought they occur more often in overweight or obese women because being overweight increases the level of oestrogen in the body.
Women who've had children have a lower risk of developing fibroids, and the risk decreases further the more children you have.
Types of fibroids
Fibroids can grow anywhere in the womb and vary in size considerably. Some can be the size of a pea, whereas others can be the size of a melon.
The main types of fibroids are:
- intramural fibroids – the most common type of fibroid, which develop in the muscle wall of the womb
- subserosal fibroids – fibroids that develop outside the wall of the womb into the pelvis and can become very large
- submucosal fibroids – fibroids that develop in the muscle layer beneath the womb's inner lining and grow into the cavity of the womb
In some cases, subserosal or submucosal fibroids are attached to the womb with a narrow stalk of tissue. These are known as pedunculated fibroids.
Treatment for fibroids isn't needed if they aren't causing symptoms. Over time, fibroids will often shrink and disappear without treatment, particularly after the menopause.
If you do have symptoms caused by fibroids, medication to help relieve the symptoms will usually be recommended first.
There are also medications available to help shrink fibroids. If these prove ineffective, surgery or other less invasive procedures may be recommended.
Read more about treating fibroids .
If your doctor suspects fibroids, they'll usually carry out a pelvic examination to look for any obvious signs.
They may also refer you to a local hospital for further tests outlined below to confirm a diagnosis or rule out other possible causes of your symptoms.
Sometimes fibroids are only discovered during routine gynaecological (vaginal) examinations or tests for other problems, because they often don't cause any symptoms.
One of the main tests carried out to diagnose fibroids is an ultrasound scan . This is a painless scan that uses a probe to produce high frequency sound waves to create an image of the inside of your body.
Two types of ultrasound scan can be used to help diagnose fibroids:
- an abdominal ultrasound scan – where the ultrasound probe is moved over the outside of your tummy (abdomen)
- a transvaginal ultrasound scan – where a small ultrasound probe is inserted into your vagina
Images produced by these scans are transmitted to a monitor so your doctor can see if there are any signs of fibroids.
If an ultrasound scan suggests you have fibroids, you may be referred to a gynaecologist (a specialist in the female reproductive system) for the tests described below.
A hysteroscopy is where a small telescope (hysteroscope) is inserted into your womb through the vagina and cervix, so your doctor can examine the inside of your womb. It takes about five minutes to carry out.
A local anaesthetic or general anaesthetic may be used so you won't feel any pain during the procedure. However, most women don't need anaesthetic. Some women experience cramping during the procedure.
A hysteroscopy is most often used to look for fibroids within your womb (submucosal fibroids).
A laparoscope is a small telescope with a light source and camera at one end. The camera relays images of the inside of the abdomen or pelvis to a television monitor.
During a laparoscopy , a surgeon will make a small incision in your abdomen. The laparoscope will be passed into your abdomen to allow the organs and tissues inside your abdomen or pelvis to be examined. General anaesthetic is used, so you'll be asleep during the procedure.
A laparoscopy can be used to look for fibroids outside your womb (subserosal fibroids) or fibroids in the layer of muscle surrounding the womb (intramural fibroids) that have affected its size and shape.
In some cases, a small tissue sample ( biopsy ) may be removed during a hysteroscopy or laparoscopy for closer examination under a microscope.
Treatment may not be necessary if you have fibroids but don't have any symptoms, or if you only have minor symptoms that aren't significantly affecting your everyday activities.
Fibroids often shrink after the menopause , and your symptoms will usually either ease or disappear completely.
If you have fibroids that need treatment, your doctor may recommend medication to help relieve your symptoms. However, you may need to see a gynaecologist (specialist in the female reproductive system) for further medication or surgery if these are ineffective. See your doctor to discuss the best treatment plan for you.
The various treatments for fibroids are outlined below. You can also read a summary of the pros and cons of the treatments for fibroids , allowing you to compare your treatment options.
Medication for symptoms
Medicines are available that can be used to reduce heavy periods , but they can be less effective the larger your fibroids are. These medications are described below.
Levonorgestrel intrauterine system (LNG-IUS)
The levonorgestrel intrauterine system ( LNG-IUS ) is a small, plastic, t-shaped device placed in your womb that slowly releases the progestogen hormone levonorgestrel. It stops your womb lining growing quickly, so it's thinner and your bleeding becomes lighter.
Side effects associated with LNG-IUS include:
- irregular bleeding that may last for more than six months
- breast tenderness
- in some cases, no periods at all ( absent periods )
LNG-IUS also acts as a contraceptive, but doesn't affect your chances of getting pregnant after you stop using it.
If LNG-IUS is unsuitable – for example, if contraception isn't desired – tranexamic acid tablets may be considered. They work by stopping the small blood vessels in the womb lining bleeding, reducing blood loss by about 50%.
Tranexamic acid tablets are taken three or four times a day during your period for up to four days. Treatment should be stopped if your symptoms haven't improved within three months.
Tranexamic acid tablets aren't a form of contraception and won't affect your chances of becoming pregnant.
Indigestion and diarrhoea are two possible side effects of tranexamic acid tablets.
Non-steroidal anti-inflammatory drugs (NSAIDs) , such as ibuprofen and mefenamic acid, can be taken three times a day from the first day of your period until bleeding stops or reduces to manageable levels.
NSAIDs work by reducing your body's production of a hormone-like substance called prostaglandin, which is linked to heavy periods.
Anti-inflammatory medicines are also painkillers, but they aren't a form of contraception.
Indigestion and diarrhoea are common side effects of NSAIDs.
The contraceptive pill
The contraceptive pill is a popular method of contraception that stops an egg being released from the ovaries to prevent pregnancy.
As well as making bleeding lighter, some contraceptive pills can help reduce period pain .
Your doctor can provide you with further advice about contraception and the contraceptive pill.
Oral progestogen is synthetic (man-made) progesterone (one of the female sex hormones) that can help reduce heavy periods. It's usually taken as a daily tablet from days five to 26 of your menstrual cycle, counting the first day of your period as day one.
Oral progestogen works by preventing the womb lining growing quickly. It's not a form of contraception, but it can reduce your chances of conceiving while you're taking it.
The side effects of oral progestogen can be unpleasant and include weight gain, breast tenderness and short-term acne .
Progestogen is also available as an injection to treat heavy periods. It works by preventing the lining of your womb growing quickly.
This form of progestogen can be injected once every 12 weeks for as long as treatment is required.
Common side effects of injected progestogen include:
- weight gain
- irregular bleeding
- absent periods
- premenstrual symptoms, such as bloating, fluid retention and breast tenderness
Injected progestogen also acts as a contraceptive. It doesn't prevent you becoming pregnant after you stop using it, although there may be a significant delay (up to 12 months) after you stop taking it before you're able to get pregnant.
Medication to shrink fibroids
Gonadotropin releasing hormone analogues (GnRHas)
If you're still experiencing symptoms related to fibroids despite treatment with the above medications, your doctor can refer you to a gynaecologist. They may prescribe medication called gonadotropin releasing hormone analogues (GnRHas) to help shrink your fibroids.
GnRHas, such as goserelin acetate, are hormones that are given by injection. They work by affecting the pituitary gland which stops the ovaries producing oestrogen. The pituitary gland is a small, pea-sized gland located at the bottom of the brain. It controls a number of important hormone glands within the body.
GnRHas stop your menstrual cycle (period), but aren't a form of contraception. They don't affect your chances of becoming pregnant after you stop using them.
If you're prescribed GnRHas, they can help ease heavy periods and any pressure that you feel on your stomach. They also help improve symptoms of frequent urination and constipation .
GnRHas are sometimes also used to shrink fibroids prior to surgery to remove them.
GnRHas can cause a number of menopause-like side effects, including:
- hot flushes
- increased sweating
- muscle stiffness
- vaginal dryness
Sometimes, a combination of GnRHas and low doses of hormone replacement therapy (HRT) may be recommended to prevent these side effects.
Osteoporosis (thinning of the bones) is an occasional side effect of taking GnRHas. Your doctor can give you more information about this and may prescribe additional medication to minimise thinning of your bones.
GnRHas is only prescribed on a short-term basis (a maximum of six months at a time). Your fibroids may grow back to their original size after treatment is stopped.
Ulipristal acetate is a new method of treating fibroids that have moderate to severe symptoms. It’s only recommended for women over 18 years of age.
The treatment involves taking one tablet orally (by mouth) once a day, with a course of treatment lasting up to three months. During this time you shouldn't bleed and your fibroids will shrink.
After the initial course of treatment, you wait to see what your first two periods are like while not taking treatment. If they're still heavy, another three month course of ulipristal acetate may be recommended.
Treatment should only be started when menstruation (monthly periods ) have occurred. The first course of treatment should start during the first week of menstruation. Your doctor will be able to explain how long the intervals between treatment courses should be.
If you’re taking a course of ulipristal acetate and you miss a dose, you should take a dose as soon as possible. However, if the dose was missed by more than 12 hours, you shouldn't take the missed dose but should return to your normal dosing schedule.
Hormonal forms of contraception , such as the progestogen-only pill , the intrauterine device , or combined oral contraceptive pill aren't recommended if you're taking ulipristal acetate. Instead, you should use a barrier method of contraception, such as condoms .
The electronic Medicines Compendium (eMC) website has more information about ulipristal acetate.
Surgery to remove your fibroids may be considered if your symptoms are particularly severe and medication has been ineffective.
Several different procedures can be used to treat fibroids. Your doctor will refer you to a specialist who will discuss the options with you, including benefits and any associated risks.
The main surgical procedures used to treat fibroids are outlined below.
A hysterectomy is a surgical procedure to remove the womb. It's the most effective way of preventing fibroids coming back.
A hysterectomy may be recommended if you have large fibroids or severe bleeding and you don't wish to have any more children.
There are a number of different ways a hysterectomy can be carried out, including through the vagina or through a number of small incisions in your abdomen (tummy).
Depending on the technique used, a hysterectomy can be carried out using a spinal or epidural anaesthetic (where the lower parts of the body are numbed). Sometimes, a general anaesthetic may be used, where you'll be asleep during the procedure.
You'll usually need to stay in hospital for a few days after having a hysterectomy. It takes about six to eight weeks to fully recover, during which time you should rest as much as possible.
Side effects of a hysterectomy can include early menopause and a loss of libido (sex drive). However, loss of sex drive usually only occurs if the ovaries have been removed.
A myomectomy is surgery to remove the fibroids from the wall of your womb. It may be considered as an alternative to a hysterectomy if you still would like to have children.
However, a myomectomy isn't suitable for all types of fibroid. Your gynaecologist can tell you whether the procedure is suitable for you based on factors such as the size, number and position of your fibroids.
Depending on the size and position of your fibroids, a myomectomy may involve making either a number of small incisions (cuts) in your tummy (keyhole surgery) or a single larger incision (open surgery).
Myomectomies are carried out under general anaesthetic, and you'll usually need to stay in hospital for a few days afterwards. After having a myomectomy, you'll be advised to rest for several weeks while you recover.
Myomectomies are usually an effective treatment for fibroids, although there's a chance the fibroids will grow back and further surgery will be needed.
Hysteroscopic resection of fibroids
A hysteroscopic resection of fibroids is a procedure where a thin telescope (hysteroscope) and small surgical instruments are used to remove fibroids.
The procedure can be used to remove fibroids from inside the womb (submucosal fibroids), and is suitable for women who want to have children in the future.
No incisions are needed because the hysteroscope is inserted through the vagina and into the womb through the entrance to the womb (cervix). A number of insertions are needed to ensure that as much fibroid tissue as possible is removed.
The procedure is often carried out under general anaesthetic, although local anaesthetic may also be used. You can usually go home on the same day as the procedure.
After the procedure you may experience stomach cramps, but they should only last a few hours. There may also be a small amount of vaginal bleeding, which should stop within a few weeks.
Hysteroscopic morcellation of fibroids
Hysteroscopic morcellation of fibroids is a new procedure where a clinician who's received specialist training in the technique uses a hysteroscope and small surgical instruments to remove fibroids.
The hysteroscope is inserted into the womb through the cervix (neck of the womb), and a specially designed instrument called a morcellator is used to cut away and remove the fibroid tissue. The procedure is carried out under a general or spinal anaesthetic. You'll usually be able to go home on the same day.
The main benefit of hysteroscopic morcellation compared with hysteroscopic resection is that the hysteroscope is only inserted once, rather than a number of times, reducing the risk of injury to the womb.
The procedure may be an option in cases where there are serious complications. However, because hysteroscopic morcellation is a new technique, evidence about its overall safety and long-term effectiveness is limited.
Read the National Institute for Health and Care Excellence (NICE) guidance about hysteroscopic morcellation of uterine fibroids.
As well as traditional surgical techniques to treat fibroids, non-surgical treatments are also available. These are outlined below.
Uterine artery embolisation (UAE)
Uterine artery embolisation (UAE) is an alternative procedure to a hysterectomy or myomectomy for treating fibroids. It may be recommended for women with large fibroids.
UAE is carried out by a radiologist (a specialist doctor who interprets X-rays and scans). It involves blocking the blood vessels that supply the fibroids, causing them to shrink.
During the procedure, a special solution is injected through a small tube (catheter), which is guided by X-ray through a blood vessel in your leg. It's carried out under local anaesthetic, so you'll be awake but the area being treated will be numbed.
You'll usually need to stay in hospital a day or two after having UAE. When you leave hospital, you'll be advised to rest for one to two weeks.
Although it's possible to have a successful pregnancy after having UAE, the overall effects of the procedure on fertility and pregnancy are uncertain. It should therefore only be carried out after you've discussed the potential risks, benefits and uncertainties with your doctor.
Endometrial ablation is a relatively minor procedure that involves removing the lining of the womb. It's mainly used to reduce heavy bleeding in women without fibroids, but it can also be used to treat small fibroids in the womb lining.
The affected womb lining can be removed in a number of ways – for example, by using laser energy, a heated wire loop, or hot fluid in a balloon.
The procedure can be carried out either under local anaesthetic or general anaesthetic . It's fairly quick to perform, taking around 20 minutes, and you can usually go home the same day.
You may experience some vaginal bleeding and tummy cramps for a few days afterwards, although some women have bloody discharge for three or four weeks.
Some women have reported experiencing more severe or prolonged pain after having endometrial ablation. In this case, you should speak to your doctor or a member of your hospital care team who may be able to prescribe a stronger painkiller.
It may still be possible to get pregnant after having endometrial ablation, but the procedure isn't recommended for women who want to have more children because the risk of serious problems, such as miscarriage , is high.
The Royal College of Obstetricians and Gynaecologists (RCOG) have more information about endometrial ablation. See their leaflet called Information for you after an endometrial ablation.
There are also two relatively new techniques for treating fibroids that use magnetic resonance imaging (MRI) . They are:
- MRI-guided percutaneous laser ablation
- MRI-guided transcutaneous focused ultrasound
These techniques use MRI to guide small needles into the centre of the fibroid being targeted. Laser energy or ultrasound energy is passed through the needles to destroy the fibroid.
These treatment methods can't be used to treat all types of fibroids, and the long-term benefits and risks are unknown. As these procedures are relatively new, they're not yet widely available in the UK.
Research is still being carried out, but there's some evidence to suggest that these non-invasive procedures have short- to medium-term benefits when performed by an experienced clinician.
However, the effects on pregnancy and women who want to have a baby in the future aren't fully known, so this should be taken into consideration.
Complications of fibroids
Most women don't experience any symptoms of fibroids, but they can cause significant problems in rare cases.
The likelihood of complications occurring depends on factors such as the position of the fibroids and their size. Some main complications are outlined below.
Problems during pregnancy
If fibroids are present during pregnancy it can sometimes lead to problems with the development of the baby or difficulties during labour.
Women with fibroids may experience tummy (abdominal) pain during pregnancy and there's a risk of premature labour . If large fibroids block the vagina, a caesarean section (where the baby is delivered through a cut in the tummy and womb) may be necessary. In rare cases, fibroids can cause miscarriage (the loss of pregnancy during the first 23 weeks).
Your doctor or midwife will be able to give you further information and advice if you have fibroids and are pregnant.
Infertility (the inability to become pregnant) may occur in cases where a woman has large fibroids. Fibroids can sometimes prevent a fertilised egg attaching itself to the lining of the womb or prevent sperm reaching the egg, although this is rare.
If you have a submucosal fibroid (a fibroid that grows from the muscle wall into the cavity of your womb), it may block a fallopian tube, making it harder for you to become pregnant. The fallopian tubes connect the ovaries (where the egg is released) to the womb.