Fibroids: More Common than You Think

Woman with abdominal pain
Women's Health Monthly: March 2017

"Fibroids are extremely common," says Joanna Hatfield, M.D. "The majority of women have them by the time they're in their forties."

In fact, among those women who have had a uterine ultrasound for any reason, 70 to 80 percent of women have fibroids before age 50. This seems surprising, but the key is that most women never need treatment of any kind.

"Unless they cause symptoms, fibroids aren't a problem," says Dr. Hatfield. "About 20 percent of women in their forties experience symptoms."

What are Fibroids?

Fibroids are normal uterine muscle cells that grow in a ball or clump. They can grow inside or outside of the uterus, and may grow directly on the uterine wall or may hang from a stalk. They may be as small as the size of a pea or as large as a full-term pregnancy.

The cause of fibroids isn't known, but research has identified several risk factors:

  • Family history of fibroids
  • Being African American
  • Being overweight or obese
  • Consumption of red meat and alcohol, especially beer
  • Low vitamin-D levels

Because fibroids grow throughout the period of life when women are menstruating, they also become more likely as women age. The good news is that fibroids often stop growing or even shrink after menopause.

However, when women develop fibroids at a young age, they have more time to grow and may be more likely to cause symptoms.

"The size and location of fibroids will determine whether they cause symptoms," says Dr. Hatfield. The most common symptoms are pressure on other organs from very large fibroids and bleeding problems caused by submucosal fibroids (those positioned inside the uterus in the uterine wall).

Fibroids and Cancer

While fibroids are tumors, they are benign (non-cancerous).

"Fibroids do not become cancerous," says Dr. Hatfield. "Sometimes masses seen on ultrasound can look like fibroids, but turn out to be cancer."

In women with uterine masses that are causing symptoms, just one in every 200 to 500 is a cancerous tumor. The rest are fibroids.

Fibroids and Fertility

For most women, fibroids do not impact fertility. However, submucosal or very large fibroids can impact fertility and pregnancy outcomes.

"Depending on their size and position, we may recommend surgical removal of fibroids prior to pregnancy," says Dr. Hatfield. "Very small fibroids and fibroids on the outside of the uterus are unlikely to cause problems."

Treating Symptomatic Fibroids

The OHSU Center for Women's Health is home to the only multi-disciplinary fibroid program in the region. Dr. Hatfield, an obstetrician and gynecologist, works with experts from radiology and fertility to help women with fibroid symptoms. Often, Dr. Hatfield sees these patients in clinic, but the team also reviews cases sent to them by other OHSU providers seeking direction.

"The team talks about each case, looks through images, and comes up with recommended treatment options," says Dr. Hatfield. "We help women tailor a plan that really fits their situation, preferences, and goals."

Future Treatments

Recent research on Selective Progesterone Receptor Modulators (SPRMs), currently used in large doses for emergency contraception, has yielded great results.

"The FDA is poised to approve a smaller dose taken over five weeks for women with fibroids," says Dr. Hatfield. "The medication has been shown to reduce bleeding and may even shrink fibroids over time."

Dr. Hatfield is also involved in research studies through the Women's Health Research Unit. Two studies looking at treatment options have occurred so far, and another is in the planning stages. 

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