Despite more than 20 years of intensive research and references to the disease as far back as Ancient Egypt (endometriosis was described in Egyptian papyrus texts as the wandering womb), the cause of endometriosis remains a mystery. However, recent research into the role of the immune system indicates that certain tissues in the abdominal cavity may stimulate endometrial growth.
Other research in Canada points to environmental factors. A study of monkeys showed exposure to dioxins led to a significantly higher survival of endometrial implants and larger implants compared with a control group. Analysis of the fluid around the ovaries in women going to fertility clinics has also revealed a broad range of chemicals, including pesticides.
Meanwhile, a report from the Genome Project reveals an increased risk among sisters and cousins of women who have the condition.
Studies of families suggest two types of endometriosis, one with early onset, characterised by severely painful periods and more subfertility, the other with a later onset and a shorter time between onset of first symptoms and diagnosis of the disease, with less effect on fertility.
www.medicine.ox.ac.uk/ndog/oxegene.htm