lodge in an ovary, Fallopian tube, uterine muscular tissue, abdominal cavity, on the bladder or in the rectum. It is affected by the sexual hormone cycle, and itself menstruates. Blood in the abdominal cavity causes severe pain, and the principal symptom is monthly recurrence of such pain; the patient also experiences pain during intercourse, and infertility can result. Diagnosis is by laparoscopy, and treatment with hormones to suppress the menstrual cycle. The patches of tissue can sometimes be burnt away during laparoscopy; in severe cases, if medication is ineffective, the womb and ovaries are removed (hysterectomy) with the endometriosis, but only in women who want no more children. Pregnancy has a favourable effect on the condition.