By age 50, about seven out of 10 white women and more than eight out of 10 black women in the United States have a condition about which they may not even be aware: fibroids, or noncancerous tumors in the muscles of the uterus.
These growths often are small and don't cause symptoms; they may wax and wane over time. But it is 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.
The condition is a major cause of lost work days and is estimated to cost the United States billions of dollars annually in medical and surgical treatment and lost work time. 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 gynecology 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 3½ 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 diarrhea 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 gynecology at the 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 gynecologist for help.
"The symptoms were so horrible," said Venable, who was working as a construction manager in Illinois 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 anemic, it's very challenging."
Venable, now 43 and living in Baltimore, 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, the surgical removal of the uterus.
"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 tumors so that they would be easier to remove. But the drug caused menopausal side effects and the doctors were unable to remove the tumors surgically.
Several years later, she underwent two surgeries that were slightly more successful; some of the tumors 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 gynecology 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.
Black women are more likely to develop them at a younger age than white women, to delay seeking medical help, to develop larger fibroids and to undergo hysterectomy and myomectomy (surgical removal of just the tumor). The Harris survey also reported that black fibroid patients were more likely to report having heavy periods, abdominal pain and anemia than white respondents.
"I've looked at other diseases, such as cancers and heart disease, and can't find one where the magnitude of disparities is so high," Stewart said.
Yet most of the research on the genetic causes of fibroids has occurred in white women of northern European descent and Japanese women, according to a recent review in the American Journal of Obstetrics and Gynecology.
"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. 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. In a study of black women, those who consumed less than one serving of dairy each day were at increased risk compared with those who consumed two or more servings.
There are many reasons why less research has been devoted to fibroids than to other health conditions, according to Myers and Stewart. Fibroids aren't fatal, and the prevailing medical wisdom has long been that they can be cured with a hysterectomy, the second most common surgical procedure in premenopausal women in the United States.
But hysterectomy has risks, and its long-term effects, such as bowel and bladder problems, dementia, osteoporosis and heart disease have not been fully elucidated, according to Stewart.
Several new fibroid interventions have been introduced over the past decade, such as hormonal treatments and radiological procedures, but there is a lack of information about how they compare in terms of controlling pain and bleeding, preventing growth of new fibroids, and allowing patients to remain fertile.
Fibroid researchers hope that a $20 million research initiative by the Patient Centered Outcomes Research Institute, which was created as part of the Affordable Care Act, will help answer women's questions about their treatment options. Stewart and other scientists hope this initiative will also improve understanding of how to prevent fibroids as well as why women with fibroids appear to have an increased risk of high blood pressure and heart disease.
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.
"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."