Clinical Question: How common are uterine fibroids in middle-aged women?

Setting: Population-based

Study Design: Cross-sectional

Synopsis: No previous study conducted in the United States has screened randomly selected women for the presence of uterine fibroids. In this study, women (n = 1,364) 35 to 49 years of age who were members of a prepaid health plan were randomly selected for screening. The population of the health plan was urban, approximately 50 percent black, and had a broad socioeconomic base. Because fibroids diminish after menopause, the authors postulated that a woman's cumulative incidence of fibroids in her late 40s would approach her lifetime risk of developing them.

Presence of fibroids was determined by ultrasonography for premenopausal women with an intact uterus, by medical records when available for patients who had undergone hysterectomy, and otherwise by self-report. Hysterectomy with a diagnosis of fibroids was more common in black women (12 percent) than in white women (5 percent). The cumulative incidence of fibroids was estimated to be higher than 80 percent in black women and almost 70 percent in white women. Women of other ethnic groups were not studied. Fibroids were present on ultrasound examination in 51 percent of women without a previous diagnosis of fibroids.

Bottom Line: If you look for uterine fibroids by ultrasonography in women in their late 30s and 40s, you will find them the majority of the time. (Level of Evidence: 1b)