What are the causes and symptoms of endometriosis?
Although the exact cause of endometriosis is unknown, a number of theories have been put forward. Some of the more popular ones are: • Implantation theory. Originally proposed in the 1920s, this theory states that a reversal in the direction of menstrual flow sends discarded endometrial cells into the body cavity where they attach to internal organs and seed endometrial implants. There is considerable evidence to support this explanation. Reversed menstrual flow occurs in 70–90% of women and is thought to be more common in women with endometriosis. However, many women with reversed menstrual flow do not develop endometriosis. • Vascular-lymphatic theory. This theory suggests that the lymph system or blood vessels (vascular system) is the vehicle for the distribution of endometrial cells out of the uterus. • Coelomic metaplasia theory. According to this hypothesis, remnants of tissue left over from prenatal development of the woman’s reproductive tract transforms into endometrial cells
