Why Do Uterine Fibroids Cause Heavy Periods

The uterus has three layers. One is the endometrium, which comes off every month during a menstrual cycle, then there’s a thick muscular layer, and then there’s an outer lining. Uterine fibroids can exist in several different layers of the uterus. Fibroids that are close to, or pushing out against, the inside layer of the endometrium result in abnormal blood vessels being present in that layer. When those blood vessels get exposed during the menstrual cycle, excess bleeding can occur.