**6. The negative laparoscopy**

A comparison of the results of pain testing was done in women investigated for pelvic pain between 69 with confirmed endometriosis compared to 35 who had a negative laparoscopy [15]. When women with a negative laparoscopy were compared to those with confirmed endometriosis, there were no differences in age, gravidity, parity, menarche, and frequency of dyspareunia or duration of severe dysmenorrhea. There were no differences in the frequency of abdominal wall allodynia or of pressure pain thresholds. These tests give validation to the women who otherwise have no explanation and it also raises the possibility that dysmenorrhea may be the source of the pelvic pain. These results are consistent with testing of women with persistent pelvic pain with and without endometriosis [3].
