Abstract: Objective: To observe the effects of electroacupuncture at Hegu, Sanyinjiao and Zusanli points in labor analgesia and to investigate the analgesic mechanism. Methods: 80 cases maternal were randomly divided into two groups, Group A: transcutaneous electrical nerve stimulation (TENS) group (Use TENS to Hegu, Sanyinjiao, Zusanli point in labor until the fetus was delivered); Group B: control group. Record VAS at different times, delivery outcome and perinatal outcome. Collect venous blood in both groups at the time of postpartum (T0), uterus opens to the full extent (T1) to test the concentration of β-EP, Cor and ACTH. Results: The VAS scores of group A were significantly lower than those of group B at each time points in incubation period of labor (P＜0.05), but there was no significant difference in both groups after active phase of labor (P＞0.05). The stage of labor in group A was shorter than that in group B (P＜0.05). There was no significant difference in postpartum hemorrhage and Apgar score between two groups (P＞0.05). Compared with T0, the concentrations of β-EP, Cor and ACTH in peripheral blood of both groups were significantly increased at T1 (P＜0.05). The concentration of β-EP at T1 was significantly higher in group A than that in group B (P＜0.05). Cor and ACTH concentrations were lower than those in group B (P＜0.05). Conclusions: Electroacupuncture at Hegu, Sanyinjiao, Zusanli points can effectively relieve the pain in incubation period of labor, shorten the stage of labor and increase the safety of maternal-neonatal. Its analgesic effect was associated with the increase of neurotransmitter β-EP content and the effective reduction of maternal stress response. Further researches should be aimed to improve the analgesia effect in the active phase of labor.

Key words: Transcutaneous electrical nerve stimulation, Parturition, Analgesia, Labor, obstetric, Point LI4 (hegu), Point SP6 (sanyinjiao), Point ST36 (zusanli)