The exact cause of uterine fibroids is unknown. What is known is that these benign tumors respond to hormones, specifically estrogen. Women are most likely to develop leiomyomas between the onset of menstruation and the beginning of menopause. Young women who have yet to enter menstruation rarely develop fibroids, and after menopause the growths usually diminish in size and symptoms decrease in severity.
The chance of developing fibroids increases as women age, reaching a high point shortly before menopause. Approximately twenty percent of women in their twenties develop fibroids. The rate increases to thirty percent between the ages of thirty and forty. After menopause, new growths are unlikely unless a woman takes estrogen supplements. Some researchers believe these statistics may not reflect true incidence rates, as women who don’t experience symptoms are rarely diagnosed. True incidence rates may be as high as seventy percent.
Oral contraceptives have been linked to increased tumor growth rates, although studies remain open to debate.
All this suggests is that hormones play a large role in leiomyoma growth. However, while menstruation and hormones may increase growth rates, the underlying cause of the condition remains a mystery.
African American Ethnicity
Women of African American ethnicity are three to nine times more likely to develop fibroids than other women, and develop symptoms at younger ages. Asian women fall into the lowest risk group. The heightened risk for African American women has prompted some researchers to suggest a genetic predisposition for the condition. Of course, environment, lifestyle, and cultural differences may also play a role in determining ethnicity risk factors.
Obesity and Diet
Obesity has been associated with fibroids, although the condition may also occur before weight gain. Obesity has also been linked to increased estrogen production. A diet rich in red meats, particularly beef and ham, may also increase the probability of developing leiomyomas. Some protection may be found in a diet high in fruits, green vegetables, and fish.
Lowering the Risk
Eating a balanced diet and maintaining a healthy weight may help lower risk levels. Oddly enough, smoking appears to reduce risk levels, although the health dangers associated with smoking by far outweigh the risks associated with fibroid growth. For reasons that remain unclear, women who have had two or more live birth pregnancies are also less likely to develop fibroids.
Ultimately, menopause is the one factor that truly lowers the risk of fibroid development. As reproductive hormones, including estrogen, drop during menopause, tumor growth slows and new growths rarely appear.