Hormonal Imbalance
The imbalance of estrogen and progesterone, the two hormones responsible for triggering the uterine lining to develop during each menstrual period to prepare the body to become pregnant, can lead to fibroids. Changes in estrogen and progesterone concentrations in the body, which are different from normal levels, can cause fibroids to grow in the uterine walls and on the outer muscles. Fibroids contain more estrogen and progesterone receptors than healthy muscle cells in the uterus. These uterine fibroid tend to shrink after menopause because of the decrease in hormone production.
