Causes of fibroids

Fibroids are most common in women in their 40s and 50s, towards the end of the reproductive years. They are more common in women of Afro-Caribbean origin, who also tend to be affected at a younger age. Fibroids are more likely to be found in women who have had no children or who only have one child. Obesity (being very overweight) is also associated with an increased risk of developing fibroids. They do not appear to run in families.

Symptoms of fibroids

Heavy periods

Up to half of all women with fibroids have heavy periods. In some cases, this can lead to anaemia. Fibroids do not usually cause any problems with the menstrual cycle, such as bleeding between periods.

Pressure symptoms

Fibroids tend to enlarge the uterus. This may lead to lower abdominal discomfort or backache, or may press on the bladder causing such as needing to pass urine more often than normal. The uterus may also press on the rectum causing constipation. Some women experience pain or discomfort (dyspareunia) during sexual intercourse because of fibroids.

Problems with fertility

Fibroids can affect the shape and internal environment of the uterus. They can make it more difficult to conceive but they only account for about 3% of the total cases of infertility.


Fibroids can cause discomfort because of pressure symptoms. Heavier periods can lead to increased period pains. Severe pain is quite rare but can occur if a fibroid grows on a stalk, which then twists (torsion) or if a fibroid outgrows its blood supply causing it to break down (degeneration).

Diagnosis of fibroids

A doctor may suspect fibroids if he or she feels an enlarged uterus during a pelvic examination (an "internal"). An ultrasound scan is a useful way of confirming the presence of fibroids. Here, a probe is placed on the woman's lower abdomen and sound wave signals are translated into pictures on a screen.

Fibroids can be detected by chance in this way when women have ultrasound scans during pregnancy. Fibroids can also be detected by hysteroscopy, where a small telescope is passed through the cervix to view the inside of the uterus, or by laparoscopy, where a camera is passed into the abdomen through a keyhole incision and the outer wall of the uterus can be seen.

Treatment of fibroids

Fibroids don't need to be treated if they cause no symptoms, or only mild symptoms, and if the diagnosis is certain. A repeat ultrasound scan may be carried out to ensure that the fibroids are not growing too rapidly.


There are no long-term drug treatments that can "cure" fibroids. However, drugs are available that can help relieve symptoms.

One group of drugs aimed at reducing the size of fibroids are called gonadotrophin releasing hormone analogues (GnRH analogues). These drugs stop the ovaries from producing hormones. Their effect is sometimes described as a "medical menopause" and they can cause menopausal symptoms such as hot flushes. However, there are increased risks of harmful side effects such as osteoporosis (thinning of the bones) if they are given for more than six months. They may be used to control symptoms in women who are close to the menopause for whom symptoms may soon be about to improve anyway.

GnRH analogues are sometimes given before surgery on the uterus because shrinking the fibroids makes the operation easier.


  • Hysterectomy – this is a major operation to remove the uterus, usually via a "bikini-line" cut in the abdomen or, if the fibroids are not too large, via the vagina.
  • Myomectomy – this is the removal of individual fibroids, leaving the uterus intact. It is usually only considered for women who still wish to have a baby.
  • Hysteroscopic resection – fibroids within the uterus can sometimes be removed during hysteroscopy using a hot wire loop (diathermy).
  • Uterine artery embolisation – this is a new technique in which the blood supply to a fibroid is blocked, causing the fibroid to shrink. It is still undergoing research and is not yet widely available.

Fibroids and pregnancy

Fibroids are often detected at a routine scan during pregnancy. They do not necessarily cause any problems. However, there is an increased risk of miscarriage, premature labour and bleeding in women who have fibroids so it’s important to consider seeking specialist care from an obstetrician.

Most fibroids (around 80%) do not increase in size during pregnancy despite the extra hormones. Fibroids sometimes cause a severe abdominal pain during pregnancy if they break down (this is called red degeneration). The treatment for this is rest and painkillers.


Fibroids and cancer

Cancer arising in a fibroid is very rare. However, surgery to remove fibroids may still be recommended if there are symptoms of pain, bleeding and/or rapid growth of fibroids, especially in a post-menopausal woman.

Last Updated: Aug 2017
Please note that all medical health articles featured on our website have been reviewed by Quality Healthcare doctors. The articles are for general information only and are not medical opinions nor should the contents be used to replace the need for personal consultation with a qualified health professional on the reader’s medical condition.