OBJECTIVETo observe the difference in the analgesic effect on primary dysmenorrheal between acupuncture and sham acupuncture at Sanyinjiao (SP 6) during menstrual pain and evaluate the impact of psychological effect on acupuncture analgesia.

METHODSSixty subjects were randomized into an acupuncture group and a sham acupuncture group, 30 cases in each one. The conventional acupuncture and sham acupuncture were applied to Sanyinjiao (SP 6) on bilateral sides when menstrual pain began to attack and needles were retained for 30 min each time. Three menstrual cycles were required. The visual analogue scale (VAS) was adopted to determine the scores before and 0. 5 h, 1 h, 3 h, 6 h and 12 h after acupuncture during menstrual pain in each cycle separately.

RESULTSIn the acupuncture group, VAS score at each time point after acupuncture was reduced as compared with that at the previous one during menstrual pain in each menstrual cycle, indicating the significant difference (all P<0. 05). In the sham acupuncture group, the scores in 6 h and 12 h of acupuncture were reduced as compared with the previous one, indicating the significant difference (all P<0. 05). After acupuncture, VAS score at each time point in the acupuncture group was lower than that in the sham acupuncture group (all P<0. 05).

CONCLUSIONThe conventional acupuncture at Sanyinjiao (SP 6) achieves the significant analgesic effect on primary dysmenorrheal. The psychological placebo effect of sham acupuncture has no obvious impact on acupuncture analgesia.