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Uterine fibroids (also called leiomyomas) are non-cancerous growths that form in the muscular wall of the uterus. Fibroids can cause symptoms such as heavy menstrual bleeding, painful cramps, iron-deficiency anemia, bloating, constipation, urinary issues, and fertility challenges.
The exact cause of fibroids is not fully understood, but certain factors can encourage their development and progression.
If you suspect that you might have fibroids, a fibroid specialist can confirm the diagnosis and discuss the best treatment options for you.
What Causes Fibroids?
While doctors are working to fully understand what causes fibroids, they have identified several key factors that increase the likelihood of their development. Research has shown a connection between genetics, hormones, and growth-related factors.
Risk factors indicated by medical research that can increase your chances of developing fibroids include family history, ethnicity, and age. Factors related to lifestyle and health status that might be modified include body mass index (BMI) and a vitamin D deficiency. The following overview explains the possible causes of uterine fibroids and how they may influence fibroid growth.
Fibroid Risk Factors
Although risk factors increase the likelihood of developing uterine fibroids, they are not the only cause of fibroids in every woman. Some of these risk factors are non-modifiable, such as age and family history, while others, like weight and vitamin D levels, are modifiable.
While no single lifestyle change can prevent fibroids, understanding your potential risk can help you make informed healthcare decisions.
Family History
Family history is considered one of the strongest possible causes of uterine fibroids. Women with a strong family history, particularly a mother or sister diagnosed with fibroids, have an increased likelihood of developing them.
Some studies suggest a maternal history of fibroids specifically can increase a person’s risk up to three times compared to the average. 7
The Role of Hormonal Imbalance
Fibroid growth is heavily influenced by the balance of two key hormones: estrogen and progesterone.6
Estrogen: Uterine fibroids are considered estrogen-dependent, which means higher levels of this hormone cause fibroids to grow.
Progesterone: Progesterone acts as a natural counterbalance to estrogen and can help deter fibroid growth. Without enough progesterone, your body’s estrogen levels can go unchecked, which may stimulate the growth of fibroids.
Estrogen and progesterone levels change naturally during your menstrual cycle, pregnancy, and before menopause. These hormonal fluctuations can impact your chances of developing fibroids. Here’s how:
- Women who start their period at a younger age are more at risk for fibroids because they’re exposed to estrogen for longer.
- Estrogen increases during pregnancy, which may be why fibroids sometimes grow rapidly during this time.
- Estrogen levels start to decrease in the years leading up to menopause — known as perimenopause. This decrease might cause fibroids to shrink, leading to less noticeable symptoms. However, some women don’t experience a decrease in symptoms, even after menopause.
Insulin-Like Growth Factors
Insulin-like growth factor (IGF) is another hormone that may contribute to fibroids. IGF helps regulate tissue growth and repair, but elevated levels may encourage fibroid cell growth.
Extracellular Matrix (ECM)
Uterine fibroids have also been linked to increased extracellular matrix (ECM) production. ECM is a substance that causes cells to stick together and gives fibroids their fibrous consistency. Higher ECM production may promote fibroid growth by storing growth factors and altering cellular behavior within the uterus.
Vitamin D Deficiency
A broad consensus in scientific literature suggests that vitamin D deficiency may be a potential cause of fibroids.8 Emerging research suggests that vitamin D3 can help reduce growth, though larger clinical trials are still needed to confirm its effectiveness as a treatment.
High BMI
Women who have a high BMI or weight-related conditions are more at risk of developing fibroids, as fat cells produce estrogen. Since excess body weight may influence hormone levels, this higher estrogen exposure may contribute to fibroid development.
Birth Control Pills
The impact of hormonal birth control on fibroids is not fully understood. Because oral contraceptives alter your hormone levels, their effect may vary: some research suggests they may manage heavy bleeding or symptoms, while other evidence indicates they may influence fibroid growth.1
More research is needed to determine whether birth control may be a potential cause for fibroids. As such, it’s best to talk to your doctor about what’s right for you.
Treatment Options for Uterine Fibroids
The best treatment for you will depend on symptom severity, fibroid characteristics, and future fertility goals. The specialists at USA Fibroid Centers treat fibroids with a minimally invasive procedure called uterine fibroid embolization (UFE). UFE is a minimally invasive, uterus-preserving treatment that blocks blood flow to fibroids, causing them to shrink. Many patients choose UFE because it is an outpatient procedure that requires no hospital stay and offers a shorter recovery time than surgery.
How USA Fibroid Centers Can Help
Knowing the possible causes of uterine fibroids can help you take control of your reproductive health. Our specialists at USA Fibroid Centers focus exclusively on diagnosing and treating fibroids using advanced ultrasound imaging to detect fibroids and develop personalized treatment plans.
If you’re concerned about uterine fibroids, schedule an appointment with one of our specialists at a nearby fibroid center today.
FAQs About Causes of Fibroids
What are the main causes of fibroids?
There is no single known cause of fibroids. Certain factors may contribute to fibroid growth, though, including hormonal fluctuations, genetics, race, pregnancy, vitamin D deficiency, insulin-like growth factor, and increased extracellular matrix production.
How to stop fibroids from growing?
Fibroids cannot be fully prevented and typically do not go away on their own, which is why medical evaluation is so important. However, maintaining a healthy weight, exercising regularly, consuming vitamin D-rich foods, and staying hydrated may support overall wellness.2
Who is most likely to get fibroids?
Those who are most likely to get fibroids are Black women of reproductive age. Although Black women often experience more severe and earlier-onset symptoms compared to white women, some studies also suggest Latina and Hispanic women may have an elevated risk.3
At what age do fibroids usually develop?
Fibroids usually develop after age 35, though they can occur earlier in reproductive years as well.
Sources:
- “Uterine fibroids: When is treatment with hormones considered?” Institute for Quality and Efficiency in Health Care. U.S. National Library of Medicine, March 24, 2020.
- Tinelli, Andrea, Marina Vinciguerra, Antonio Malvasi, Mladen Andjić, Ivana Babović, and Radmila Sparić. “Uterine Fibroids and Diet.” International journal of environmental research and public health. U.S. National Library of Medicine, January 25, 2021. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7908561/
- Mostafavi, Beata. “Understanding Racial Disparities for Women with Uterine Fibroids.” University of Michigan, August 12, 2020.
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4170830/
- Northwell Health. “Expert Insights.” 11 Unexpected Signs of hormonal imbalance | Northwell Health, November 27, 2018.
- Fibroids, Office on Women’s Health, U.S. Department of Health & Human Services, Feb. 28, 2025
- Donna Day Baird, Vitamin D and the risk of uterine fibroids, Epidemiology Branch, National Institute of Environmental Health Sciences, 2013