Causes of Uterine Fibroids
Also known as uterine leiomyomata, uterine fibroids are abnormal growths that form from muscular tissue in the uterus. Ranging in size, the growths can occur singly or in numbers. The most common type of non-cancerous tumors in women of childbearing age, uterine fibroids are estimated to occur in three out of four women during their lifetime. Uterine fibroids aren't associated with an increased risk of uterine cancer. Uterine fibroids may be caused by any one or a number of the following reasons:

1. Estrogen excess. 
Fibroids grow in times of high estrogen production for example after the menses and during pregnancy. Exogenous estrogens can be found in the environment such as processed food, pesticides, cosmetics, and plastics. Other contributing factors to increased estrogen levels include poor digestion and constipation.

2. Low progesterone levels. 
This can create an underactive thyroid and anovulatory cycles.  Low progesterone levels may be caused by excess stress.
-- Long term use of oral contraceptive pills.
-- Chronic constipation.
-- Dietary factors. Diets high in dairy, eggs, meat, greasy foods, and caffeine.