These growths often are small and don't cause symptoms; they may wax and wane over time. But it's not unusual for them to occur in clusters and to enlarge the uterus to the size of an advanced stage pregnancy.

Large fibroids can cause symptoms such as heavy bleeding, the need to urinate frequently, constipation, bloating and pain.

In some instances, fibroids can affect a woman's ability to become pregnant and to carry a pregnancy to term. Fibroids can also have a negative effect on a woman's quality of life, according to one study, which linked the condition to lower self-esteem, body-issue anxieties and fears about relationships and sexuality.

"When you look at the burden of disease - not only its impact on quality of life but also on women's ability to work and take care of their kids - it's really quite stunning," said Evan Myers, a professor in the department of obstetrics and gynaecology at Duke University School of Medicine.

Yet many women who have fibroid symptoms delay reporting them. In a recent Harris Interactive survey of more than 800 fibroid patients, women reported waiting 3 1/2 years, on average, before seeking help; a third said they had waited more than five years.

"I told one patient [who routinely had to miss work because of heavy bleeding]: 'If you had such severe diarrhoea that you had to stay home for three days each month, wouldn't you consider that a different level of problem or unacceptable?' " said Elizabeth Stewart, a professor of obstetrics and gynaecology at thee Mayo Clinic and author of Uterine Fibroids: The Complete Guide.

Sateria Venable knows all too well about the problems fibroids can cause. For years Venable assumed that the heavy, exhausting menstrual periods she experienced were just something she had to endure. But finally, at 26, she decided to ask a gynaecologist for help.

"The symptoms were so horrible," said Venable, who was working as a construction manager at that time. "I worked in a very male-dominated profession. If you can't keep up walking on a construction site because you're anaemic, it's very challenging."

Venable, now 43, had hoped that her doctor would be able to resolve the problem with dietary changes and medication. Instead, she was told she had extensive fibroids.

Venable was told she should consider a hysterectomy. "That sounded so crazy," she said. So she embarked on a course of medications and less drastic surgical procedures that aimed to cut out the fibroids without removing the uterus. Before the first surgery, she took leuprolide (Lupron), a medication to shrink the tumours so that they would be easier to remove. But the drug caused menopausal side effects and the doctors were unable to remove the tumours surgically.

Several years later, she underwent two surgeries that were slightly more successful; some of the tumours were removed, but in both cases they grew back within a year.

"It took a lot of recovery time, and it was only a temporary fix," she said.

The fibroid's location plays a large role in determining whether a woman will have symptoms and how the problem will be treated, according to Christine Colie, an associate professor of obstetrics and gynaecology at Georgetown University School of Medicine. "A fibroid that sticks out of the uterus into the abdomen is less likely to be problematic than a fibroid that's growing into the uterine cavity," Colie said.

"There may be common pathways" between fibroids and other medical conditions, Stewart said. "Understanding the disease is a key part of being able to provide better treatment."

Yet there has been a dearth of research into what causes fibroids, the natural course of the condition, and the benefits and risks of treatments for them. While a woman's own hormones play a role in fibroid growth, research suggests genetics is important in determining whether a woman will develop the condition.

Less is known about the exact role of diet and environmental factors on fibroid development. There are epidemiologic data suggesting that women who eat certain foods are less likely to have fibroids. One such study found that women with low levels of Vitamin D in their blood were more likely to have fibroids than women with normal Vitamin D levels. Women whose diets are heavy in red meat and low in green vegetables and citrus fruit appear to be at increased risk.

Today, Venable has, with the help of an empathetic physician, learned to control her fibroid symptoms with a combination of diet, exercise, an iron supplement and a medication, transexamic acid (Lysteda), which suppresses her bleeding enough to allow her to sleep through the night.

She also started a foundation and created a website to help other women with fibroids, and has designed and patented an undergarment for women with heavy bleeding.

"Once you reveal you are struggling with this health problem, you are shocked at how common it is," she said. "It's important for women to know there are answers."

- Washington Post