Uterine Fibroids and NIH Women's Health Research

Signs, Symptoms, and Risk Factors

Uterine fibroids are tumors that form in or around the wall of the uterus. They are typically benign, and women who have them may not show any symptoms.¹ However, in some cases, they may cause heavy or painful periods, bleeding between periods, frequent urination, pain during sex, or complications during pregnancy or labor. In rare cases, cancerous fibroids called leiomyosarcoma may occur.²

Uterine fibroids are common; they occur in 20% to 80% of women by the age of 50 years. African American women, women who are overweight, and women with a family history of fibroids have a higher risk of developing them. Women with uterine fibroids may also have concomitant gynecological conditions, such as endometriosis.³

It is currently unclear what causes uterine fibroids, although hormones appear to play a role because fibroids tend to grow during pregnancy and stop growing or shrink during menopause.² Mutations in certain genes (e.g., MED12, HMGA2) have been found in uterine fibroids, suggesting that there is a genetic component to this disorder.⁴ Some research also suggests that environmental factors, such as exposure to certain endocrine-disrupting chemicals, may increase the risk of developing uterine fibroids.^{5 , 6}

Diagnosis and Treatment

Health care providers often first detect an enlarged uterus or a mass that is consistent with a fibroid during routine pelvic examinations. The diagnosis is typically confirmed using imaging tests, most commonly ultrasound, although other imaging techniques such as magnetic resonance imaging (MRI) may also be used. In some cases, minimally invasive procedures such as hysteroscopy or laparoscopy may be performed to further evaluate the uterus and confirm the presence of fibroids.²

Some cases of uterine fibroids can be treated with gonadotropin-releasing hormone agonists, which have been shown to temporarily reduce the size of the fibroids. More severe cases may require a hysterectomy, endometrial ablation, uterine fibroid embolization, or another type of surgery.² Because the surgical treatments for uterine fibroids can affect a person's ability to get pregnant or give birth, there is a need for fertility-sparing treatments for this condition.

Ongoing Research

Current studies are exploring the genetic, hormonal, immune, and environmental factors that may influence fibroid development and growth, including potential contributions from endocrine-disrupting chemicals and factors that may underlie the higher burden of fibroids among Black women.^{5 - 7} Ongoing research is also examining the frequent co-occurrence of fibroids with conditions such as endometriosis, adenomyosis, and polycystic ovary syndrome and how these disorders may share biological pathways or affect diagnosis and treatment.^{3 , 8} In addition, investigators are working to develop and refine fertility-sparing treatment approaches that can effectively manage fibroid symptoms while preserving reproductive potential.

The Study of Environment, Lifestyle, and Fibroids (SELF) is a prospective epidemiologic study led by researchers at the National Institute of Environmental Health Sciences (NIEHS). This study focuses on African American women, who are disproportionally affected by uterine fibroids. The researchers have collected a wealth of data on early life experiences, menstrual and pregnancy history, environmental contaminants, sleep, stress, genetics, and other factors that may play a role in fibroid development.⁹

At the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), researchers are working to uncover the genetic and environmental factors that lead to uterine fibroids, as well as the biological mechanisms behind fibroid growth. In addition, NICHD researchers are investigating potential new treatments for uterine fibroids: gene therapy and laser therapies guided by magnetic resonance imaging may be viable options in the future.⁷