Fibroids are actually non-cancerous tumors that develop on the inside or outside of the uterus. The cause of fibroid tumors is still a mystery to everyone. But according to studies, estrogen is the main contributor in the development of fibroids. Some physicians note that these tumors are formed once the body reacts to the abnormal level of estrogen. However there are also experts that would contest this belief. Fibroids usually grow during pregnancy and when taking birth control pills since there extra production of the estrogen hormone. Fibroids are also believed to develop when taking estrogen supplements. But the tumor reduces in size the moment a woman reaches the menopause stage. This stage happens when the body stops releasing estrogen