What are fibroids?
Fibroids are common, non-cancerous growths found in the muscle wall of the uterus. Many women have fibroids; it’s estimated that up to 70% of women aged under 50 and up to 70-80% of women over the age of 50 years have fibroids. There are different treatment options, depending on the type, size, number and location of the fibroids.
What are the different types of fibroids?
Fibroids are also called uterine fibromyomas, leiomyomas or myomas and may grow in different layers of the uterus.
Fibroids can be found within the uterine muscle — intramural, or grow in the outer muscle layer — subserosal. They can also grow in the cavity of the uterus — submucosal.
What are the signs and symptoms of fibroids?
Many women don’t know they have fibroids, unless they have symptoms which lead to a diagnosis. It’s estimated that 20-30% of women do experience some symptoms.
Symptoms of fibroids can include:
- heavy or long periods, which can also cause iron deficiency anaemia
- painful periods
- painful sex
- bleeding in-between periods
- a feeling of heaviness in the back, bowel and bladder
- passing urine (wee) a lot
What causes fibroids?
It’s not well known what exactly causes fibroids to develop. However, the female hormones oestrogen and progesterone stimulate the growth of fibroids. Fibroids grow in women within the reproductive age-group until menopause.
Some factors increase the risk of developing fibroids:
- early first period
- being obese
- having a family history of fibroids — genetic influence
- never having given birth
- increasing age
- having polycystic ovary syndrome (PCOS)
- high blood pressure
There are also some factors that have been shown to lower your risk of fibroids:
- having more than 2 children
- having had a multiple birth
- use of Depo-Provera as a contraceptive
- use of the oral contraceptive pill
Can fibroids be prevented?
Currently, there is little scientific evidence available on how to prevent uterine fibroids. The general recommendations around prevention are to make healthy lifestyle choices such as maintaining a healthy weight. Eating fruits and vegetables may also decrease fibroid risk. Hormonal contraceptives may be associated with a lower risk of fibroids.
How are fibroids diagnosed?
Most women go to their GP with symptoms, which leads to diagnostic tests. There are a number of ways fibroids can be diagnosed, including by ultrasound — either vaginal ultrasound or abdominal ultrasound, having an MRI (magnetic resonance imaging), or by laparoscopy or hysteroscope — where a thin telescope shows the pelvic organs and the inside of the uterus.
How are fibroids treated?
Most fibroids don’t need treatment unless they are causing problems. Women who are experiencing impaired fertility, period pain, heavy bleeding or pressure symptoms will often choose to seek treatment.
There is a range of treatment options, depending on the extent of the fibroids and the severity of the symptoms. Treatment options for fibroids depend on a woman’s individual needs, including her plans for future pregnancy and whether she has had previous pregnancies.
Pain relieving medication can help to relieve period pain, and anti-inflammatories may be prescribed to reduce the heaviness of bleeding.
A Mirena IUD® may be recommended as it can help to reduce the heaviness of bleeding by slowly releasing progesterone.
The combined oral contraceptive pill can also help to reduce bleeding, but it needs to be stopped if pregnancy is planned.
Medication called GnRH agonist, which is an artificial hormone used to prevent natural ovulation, may help to reduce the size of a fibroid before a planned operation.
If you have anaemia, you may be recommended to take iron replacement.
There are several surgical options to treat fibroids.
- Uterine artery embolisation, where small, sterile particles are injected into the arteries which supply the fibroids with blood. Once the blood supply is gone, the fibroids shrink.
- Hysteroscopic myomectomy, where a fibroid that is partially or completely inside the cavity of the uterus (a submucosal fibroid) is removed under general anaesthetic.
- Abdominal myomectomy, which is the complete removal of the fibroid under general anaesthetic.
- MRI directed ultrasound technique, when high intensity focused ultrasound waves overheat the cells in the fibroid, causing it to shrink.
- Hysterectomy, where the uterus is completely removed.
Sometimes a combination of hormones is prescribed, which helps to shrink the fibroids, especially if fertility is affected. Once the hormones are stopped, fibroids can grow back.
Can fibroids affect my fertility and pregnancy?
Most women with fibroids have normal fertility and pregnancy outcomes. Only certain types of fibroids will have an impact on getting pregnant or delivery. In pregnancy, if uterine fibroids are present and large, they can impact on the position of the baby and limit their ability to move freely.
However, women with fibroids may also have higher rates of infertility and miscarriage. The size, location and number of fibroids can be important in relation to pregnancy and fertility. In some cases, caesarean section may be recommended for future births.
When should I see a doctor?
If you suspect you have fibroids and have been trying to conceive for 12 months (or 6 months if you are over 35 years of age), there could be benefits in booking an appointment with a fertility specialist.
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Last reviewed: June 2023