Fibroids are non-cancerous tumors found within the uterine walls, often resulting in a change in the size or shape of the uterus. The presence of fibroids does not increase your risk of developing uterine cancer later on. About a third of women develop fibroids sometime in their life.

Fibroids are made of muscle and fibrous tissue and vary in size from a pea to a melon. They can grow in several places:

  • Intramural fibroids, the most common type, are in the muscle wall of the uterus
  • Submucosal fibroids are in the muscle layer beneath the inner lining and grow in the uterine cavity
  • Subserosal fibroids are outside the walls of the uterus

Sometimes fibroids grow on stalks of tissue attached to the uterus. These are pedunculated fibroids.

Source: National Health Service, Fibroids, United Kingdom, 2015. Retrieved February 13th, 2018 from: https://www.nhs.uk/conditions/fibroids/

Causes of fibroids

The exact cause of fibroids is unknown, but their growth has been linked to elevated levels of estrogen and progesterone, hormones produced by the ovaries during each menstrual cycle. Certain factors can increase the risk for fibroids, including:

  • Age: Fibroids generally appear in women aged 30 to 50 due to approaching menopause, though they usually shrink after menopausal transition.
  • Race: Women of African and Caribbean descent are two to three times more likely to develop fibroids than women of other races/ethnicities.
  • Family history: Women with a mother or sister who had fibroids are more likely to develop fibroids.
  • Children: Women who have had children are at a lower risk of developing fibroids. This risk decreases further the more children one has.
  • Obesity: Women who are overweight or obese are more likely to develop fibroids.
  • Medicine: Medical treatments or devices that alter hormone levels, such as some types of birth control, can increase the risk of fibroids.
  • Diet: Women who consume large amounts of beef and pork may be at higher fibroid risk; in contrast, a diet that is rich in green vegetables and fruit is associated with lower risk.
  • Early menstruation: Women who started menstruating before age 10 are at a higher risk for fibroids than women who started menstruating after age 10.

Fibroid symptoms

Only about 1 in 3 women with fibroids experience symptoms. When symptoms do appear, they vary based on the location, size, and number of fibroids.

The most common symptoms of fibroids are:

  • Heavy menstrual bleeding
  • Menstrual period lasting longer than a week
  • Pain or pressure in the lower stomach or pelvic area
  • Lower back or leg pain
  • Frequent urination
  • Constipation
  • Pain during intercourse
  • In rare cases, fibroids are associated with reproductive issues such as infertility and miscarriages. Though women with fibroids are more likely to experience difficulties during pregnancy and childbirth, that does not mean they cannot safely carry and deliver a child; most women with fibroids have healthy pregnancies and births. Pregnant women with fibroids are not considered high risk.

Treatment for fibroids

If fibroids are not causing symptoms, they do not need to be treated. Fewer than 1 in 1,000 cases of fibroids are cancerous and having fibroids does not increase the risk of developing uterine cancer. Over time, they will often shrink and disappear on their own.
However, there are a number of ways to treat fibroids depending on how serious they are. Be sure to talk to your doctor to figure out which is the best option for you.

Managing fibroid symptoms (like pain and bleeding):

  • Over-the-counter pain relievers (such as ibuprofen, aspirin, or acetaminophen) can help with mild pain. However, with the exception of acetaminophen (Tylenol), many pain relievers thin blood as a side effect and could increase bleeding during menstruation.
  • Low-dose or progesterone-like birth control methods (e.g. Depo Provera or Mirena) can help control heavy bleeding, though they may come with their own side effects.
  • Iron supplements can help prevent anemia associated with heavy bleeding.
  • Gonadotropin-releasing hormone (Gn-RH) agonists can treat fibroids by blocking the production of estrogen and progesterone, creating a temporary postmenopausal state. As a result, menstruation stops, fibroids shrink, and anemia improves. However, Gn-RH agonists should not be used for more than three to six months as long-term use can result in bone loss.
  • Tranexamic acid (Lysteda), a nonhormonal medication, can be taken to ease menstrual periods and should only be taken on heavy bleeding days.
  • A diet rich in whole grains, Vitamins B and E, and soy products can help lower excessive estrogen levels. Many types of fish contain high levels of linolenic acid that can help alleviate cramps. Avoiding dairy products, meats that are high in saturated fats, alcohol, and excess salt may also help reduce cramping and pain.

Removing fibroids surgically:

  • Myomectomy: This surgery removes only the fibroids through 1- the vagina and cervix (hysteroscopically), 2- small incisions in the abdomen (laparoscopically), or 3- via open abdominal surgery (abdominal). It is most suitable for women who want to have children later on.
  • Myolysis: This operation first shrinks fibroids with Gn-RH agonists, then destroys the fibroids through a range of methods.
  • Uterine Artery Embolization (UAE): This process cuts off blood supply to the fibroids, causing them to shrink and die. It is more effective in treating submucosal and intramural fibroids.
  • Endometrial Ablation: This treatment removes the uterine lining in order to control abnormal bleeding. About half of the women who have this surgery stop menstruating while another third have much lighter bleeding. Women cannot become pregnant after this surgery, so it should only be used for those who do not want to have children later.
  • Hysterectomy: This surgery removes the uterus. It is the only permanent solution for fibroids and is a serious and irreversible procedure. The NWHN recommends trying alternatives to hysterectomy first, and then keeping your ovaries unless you have a family history of ovarian cancer. For more information, see the NWHN’s hysterectomy fact sheet.

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Updated February 2018

Fibroids