FACTORS INCREASING THE RISK OF ENDOMETRIOSIS1. Early onset of menstrual periods2. Heavy periods3. Painful periods4. Prolonged periods5. Allergy (eg: foods, eczema, hay fever)6. Obesity6. Family history of endometriosis eg: mother or sister7. Environmental toxins are also a possible cause of the disease as dioxin has been shown to cause disease in a factory where it was used excessively and also has been shown to cause endometriosis in monkeys.FACTORS REDUCING THE RISK OF ENDOMETRIOSIS1. Aerobic exercise of 5 hours per week which in two studies has shown a 50% reduction in the risk of recurrence.2. Childbearing reduces the risk of recurrence by about 50%.3. The contraceptive pill has a similar protective effect by preventing ovulation when there is a surge of estrogen production and spill into the pelvis.4. Smoking also reduces the risk of endometriosis, although it is obviously not a reason to continue smoking.