Transcutaneous electrical nerve stimulation in labour pain: a systematic review

OBJECTIVE: To review the effectiveness and safety of transcutaneous electrical nerve stimulation (TENS) for labour pain. DESIGN: A systematic review of randomised controlled trials of TENS in pain during labour. SAMPLE: Eight reports involving 712 women were included; 352 women received active TENS and 360 acted as controls. METHODS: Reports were sought by searching MEDLINE and the Oxford Pain Relief Database. MAIN OUTCOME MEASURES: Analgesic and adverse effect outcomes. RESULTS: Evidence for reduced pain using TENS in labour was weak. Additional analgesic interventions may be less likely with TENS (odds ratio 0.57; 95% CI 0.34-0.96), number-needed-to-treat 14 (95% CI 7.3-119). CONCLUSIONS: Randomised controlled trials provide no compelling evidence for TENS having any analgesic effect during labour. Weak positive effects in secondary (analgesic sparing) and tertiary (choosing TENS for future labours) outcomes may be due to inadequate blinding causing overestimation of treatment effects.