Types of Fibroids
Fibroids are commonly classified based on their size and location relative to the uterus.¹⁻² There are four types of fibroids: intramural, subserosal, submucosal, and pedunculated. Each are explained below so you can understand the difference between the types of fibroids. Most women with uterine fibroids have more than one type of fibroid.¹
Intramural fibroids, the most common, grow in the wall of the uterus. They may eventually enlarge to distort the uterine cavity or serosal surface. Some fibroids may be transmural and extend from the serosal to the mucosal surface.
Subserosal fibroids grow on the outside of the uterus. As they grow larger, they can cause pain due to their size or pressure put on nearby organs.
Submucosal fibroids grow just underneath the uterine lining and can crowd into the uterus cavity and lead to heavy bleeding and other more serious complications.
Pedunculated fibroids grow on small stalks inside or outside the uterus.
 Munro, M. G., Critchley, H. O. D., & Fraser, I. S. (2011). The FIGO classification of causes of abnormal uterine bleeding in the reproductive years. Fertility and Sterility, 95(7), 2204–2208.e3.