Uterine fibroids explained: symptoms, causes and treatment

What fibroids are

Fibroids are growths made of muscle and fibrous tissue that develop in or around the womb (uterus). They are also called uterine myomas or leiomyomas. They can be as small as a pea or grow to the size of a melon, and a woman may have one or many. Fibroids are almost always benign — that is, not cancer — and a cancerous change is very rare. They are extremely common, particularly in women in their 30s and 40s, and are more common in women of Black African and Caribbean heritage. Their exact cause is not fully known, but their growth is linked to the hormone oestrogen, which is why they often shrink after the menopause.

Symptoms and when they matter

Many fibroids cause no symptoms at all and are found by chance. When symptoms do occur, the most common is heavy or prolonged periods, which can lead to tiredness and iron-deficiency anaemia from blood loss. Fibroids can also cause period pain, a feeling of fullness or swelling in the lower tummy, needing to pass urine more often if they press on the bladder, constipation, back or leg pain, and discomfort during sex. Larger fibroids can make the abdomen look bloated or swollen. Occasionally fibroids affect fertility or pregnancy, depending on their size and position. Symptoms that disrupt daily life, or heavy bleeding causing anaemia, are the usual reasons treatment is considered.

How fibroids are diagnosed

Fibroids are often first suspected when a clinician feels the womb during an internal or abdominal examination, or when heavy periods are being investigated. The main test to confirm them is an ultrasound scan, either over the tummy or using a small probe placed in the vagina, which shows the number, size and position of fibroids. Sometimes further imaging such as an MRI scan is used to map larger or more complex fibroids before treatment, or a hysteroscopy — a thin camera passed into the womb — to look at fibroids growing into the womb cavity. Blood tests may check for anaemia caused by heavy bleeding. Diagnosis guides which treatments are likely to help.

Treatment options

Treatment depends on the symptoms, the size and position of the fibroids, and whether a woman wishes to preserve fertility. If fibroids cause no problems, no treatment is needed and they are simply monitored. For heavy bleeding, medicines are often tried first — including a hormone-releasing coil, other hormonal treatments, and non-hormonal medicines taken during periods to reduce bleeding and pain. Some medicines can temporarily shrink fibroids, often before surgery. Procedures include uterine artery embolisation, which cuts off a fibroid's blood supply, and surgery to remove individual fibroids (myomectomy) while keeping the womb. Removing the whole womb (hysterectomy) is a definitive option for women who have completed their family and have severe symptoms.

Living with fibroids and the outlook

For most women, fibroids are a manageable condition rather than a dangerous one. Because their growth is driven by oestrogen, fibroids commonly shrink and symptoms improve after the menopause, when hormone levels fall. Keeping an eye on symptoms, treating anaemia if periods are heavy, and reviewing options with a clinician if things change all help. Fibroids do not usually turn into cancer, and having them does not raise the risk of womb cancer. If you are planning a pregnancy, it is worth discussing fibroids with your clinician, as position and size occasionally matter. Overall, the outlook is good, and many effective treatments exist for those who need them.