Research on the body surface resistance imbalance degree at yuan-source points of three yin meridians of foot in the patients with primary dysmenorrhea

Objective To explore whether or not the changes in body surface resistance at yuan-source points of three yin meridians of foot can specifically responds the onset of primary dysmenorrhea (PD) in females of menstrual period and the before and after, so as to provide the evidence for acupoint selection in clinic. Methods A total of 90 cases of PD were recruited in a PD group and 90 healthy female undergraduates were recruited in a normal group. The yuan-source of points of three yin meridians of foot were selected, i.e. Taibai (太白SP3), Taichōng (太冲LR3) and Taixī (太溪KI3). The acupoints for control were Xuehai (血海SP10), the non-special acupoint, Xuanzhōng (悬钟GB39), the acupoint not on the relevant meridian, as well as a non-meridian point. Successively, before menstruation, on Day 1 during menstruation and on Day 3 after menstruation, the body surface resistance at the above-mentioned test sites was detected in the participants of two groups each day. The resistance imbalance degree (RID) of the bilateral acupoints was taken as the outcome indicator. The observation lasted one menstrual cycle. Results (1) Intra-group comparison: at LR3, the RID was lower on Day 1 during menstruation than that before menstruation significantly in the normal group (P ≤ 0.05). There was no significant change in RID at the same time points, but RID on Day 3 after menstruation was lower significantly than that before menstruation in the PD group (P ≤ 0.05). At SP3, KI3, SP10, GB39 and sham acupoint, there were no significant differences in RID among different time points within the same group (all P > 0.05). (2) Inter-group comparison: there were no significant differences in RID among different time points at the same point. (all P > 0.05). Conclusion RID at yuan-source points of three yin meridians of foot cannot specifically respond to PD. However, at LR3, before and after menstruation, RID changes are different between PD patients and healthy female undergraduates, which needs a further study in the future.