Why do fibroids cause different symptoms among women?

Fibroids are benign tumors made up of smooth muscle and fibrous tissue. They are very firm and hard to the touch. The hardness of these tumors along with the location of the fibroids in the uterus determines what symptoms a woman might experience, keeping in mind that most women with fibroids do not experience any symptoms.

Fibroids that are located centrally along the lining of the uterus (submucosal) can stretch the lining to cause heavy menstrual bleeding. Fibroids along the outer walls (subserosal) can cause bulk symptoms which include pain if they are located laterally to press on pelvic nerves or increased urinary frequency if they are located anteriorly (i.e. on top of the bladder). Intramural fibroids which are located in the main muscular part of the uterus can cause either heavy bleeding if they become large enough to reach the lining, or bulk symptoms if they grow outwardly enough, or both.