Leiomyomas, also called fibroids, are a group of smooth muscle tumors that are usually found in women before menopause. The smooth muscle of the uterus is where these tumors start, so they are called monoclonal.

Last Updated: February 25, 2024

Leiomyomas are the most common new growth in the pelvic area of women. 20–25% of women of childbearing age are diagnosed with leiomyomas, and 30–40% of women over the age of 40 have them. Women who start having periods at a younger age are more likely to get uterine myomas. The risk goes down as the number of term pregnancies increases.

Although experts are uncertain as to the precise causation of leiomyoma, research and clinical experience suggest the following factors: Changes in genes; hormones like estrogen and progesterone; the extracellular matrix (ECM, which is like the mortar between bricks that holds cells together); and other growth factors like the insulin-like growth factor.

Symptoms can vary based on where the fibroids are, how big they are, and how many there are. When fibroids are present, these are the most common signs and symptoms:

  • Heavy bleeding during periods;
  • Periods that last more than seven days;
  • Pelvic pressure or pain;
  • Frequent urination;
  • Constipation;
  • Pain in the back or legs;
  • Difficulty in urinating.

Most of the time, a physical exam will show an enlarged uterus that is often irregular in shape. The easiest way to confirm a clinical diagnosis is with ultrasonography.

More imaging, like magnetic resonance imaging (MRI), can help find out how much leiomyomas have become supplied with blood vessels or degenerated. An MRI can also help figure out how the leiomyomas are connected to the inside of the uterus.

A complete blood count (CBC) is needed if bleeding is the primary symptom and there is concern about anemia or other effects of repeated blood loss. A thyroid-stimulating hormone level should be checked as part of further blood work to rule out thyroid disease as the cause of abnormal bleeding if there is little reason to think that leiomyomata (a related disease) is the cause.


Many women with uterine fibroids have no symptoms or moderate, manageable symptoms. Watchful waiting may be ideal for these patients.

Doctors however prescribe drugs to address menstrual cycle symptoms like heavy bleeding and pelvic pressure by targeting hormones. Fibroids may decrease but not disappear. Examples of some medications are: Leuprolide; Goserelin; Triptorelin; and tranexamic acid which are GnRH agonists. NSAIDs, which are not hormonal, may relieve fibroids pain.

Other treatment choices include minimally invasive procedures such as uterine artery embolization, radiofrequency ablation, hysteroscopic myomectomy, and endometrial ablation. These procedures destroy the fibroids without actually removing them through surgery.

Doctors also perform focused ultrasound surgery (FUS) that is guided by an MRI. It is a non-invasive way to treat uterine fibroids while keeping the uterus. This procedure also does not require any cuts or hospital stays.

Lastly, doctors still do open surgery like abdominal myomectomy and hysterectomy.

Keeping a healthy weight and eating lots of fruits and vegetables may lower the risk of fibroid growth.  One study found that a high level of physical activity was linked to a big drop in the risk of getting fibroids, even after body mass index and other factors were taken into account.

Also, some research shows that women who use hormonal birth control may have a lower risk of getting fibroids.


Florence AM, Fatehi M. Leiomyoma. [Updated 2022 Jul 18]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK538273/

Sparic, R., Mirkovic, L., Malvasi, A., & Tinelli, A. (2016). Epidemiology of Uterine Myomas: A Review. International journal of fertility & sterility, 9(4), 424–435. https://doi.org/10.22074/ijfs.2015.4599

Mayo Clinic (2022). Uterine Fibroids. Retrieved November 13, 2022, from https://www.mayoclinic.org/diseases-conditions/uterine-fibroids/symptoms-causes/syc-20354288

Last Updated: February 25, 2024