Objective:To study the effect of electroacupuncture(EA) at "Hegu"(LI 4) with different stimulation duration in combination with needle retention in "Sanyinjiao"(SP 6) for different duration on uterine contraction in late-stage pregnant rats.Methods: A total of 50 late-stage pregnant(19

(th)

day after pregnancy) Wistar rats were randomized into control group

LI 4-EA-(20 min)+SP 6-needling(N)-(5 min)(i.e.

EA stimulation of LI 4 for(20 min) first and then SP 6 was punctured with the needle retained for(5 min) without electrical stimulation

similar expression in the following groups)

LI 4-EA-(20 min)+SP 6-N-(20 min)

LI 4-EA-(40 min)+SP 6-N-(5 min)

LI 4-EA-(40 min)+SP 6-N-(20 min) groups with 10 cases in each group according to the requirements of 2×2 factorial experiment design.In addition

other 10 non-pregnancy Wistar rats were used as normal control group.EA((20 Hz)

1-(3.5 V)) was applied to LI 4 for(20/40 min) in the abovementioned 4 EA groups respectively.A muscular tension transducer was fixed to the mid-segment of the uterus for detecting the amplitude

frequency and contractility(amplitude X frequency) of the uterine contraction. Results: In comparison with normal control group

the amplitude

frequency

and contractility of the uterine contraction in control group increased significantly(P

<

0.05).Comparison between factor A(LI 4: EA-20/40 min) and factor B(SP 6: needle kept in place for 5/20 min) among the 4 EA groups showed that 5-(10 min) and 15-(20 min) after removal of the needle

both factor A and factor B had no significant influence on the amplitude of the uterine contraction;factor B could significant raise the frequency and contractility of the uterus contraction(P

<

0.05

0.01);and the effects of SP 6-N-(5 min) in increasing the frequency and contractility were markedly superior to those of SP 6-N-20 min(P

<

0.05

0.01);while factor A had no marked influence on the frequency and contractility of the uterus.Comparison of the 4 EA groups showed that 5-(10 min) after removal of the acupuncture needle

the amplitude of the uterine contraction in LI 4-EA-20 min+SP 6-N-(5 min) group was markedly higher than that of LI 4-EA-(20 min)+SP 6-N-(20 min) group;(5 min) after needling SP 6 and 5-(10 min) after removal of needle

the frequency of uterine contraction in LI 4EA-(40 min)+SP 6-N-(5 min) group was significantly higher than that of LI 4-EA-(40 min)+SP 6-N-(20 min) group(P

<

0.05).Conclusion: EA of LI 4 plus needling SP 6 can promote the uterine contraction activity in pregnancy rats

and the best combination is EA LI 4(20 min) first plus needling SP 6(5 min) later.