Limited evidence for effectiveness of transcutaneous electrical nerve stimulation (TENS) for pain relief in labour

Clinical question: 
How effective is transcutaneous electrical nerve stimulation (TENS) for pain relief in labour?
Bottom line: 
Overall, there was little difference in pain ratings between TENS and control groups, although women receiving TENS to acupuncture points were less likely to report severe pain. The majority of women using TENS said they would be willing to use it again in a future labour. Where TENS was used as an adjunct to epidural analgesia, there was no evidence it reduced pain. There was no consistent evidence TENS had any impact on the length of labour, interventions in labour, or the wellbeing of mothers and babies.
The risk of bias in these studies was generally high. Few studies provided clear information about sequence generation or methods used to conceal group allocation. It is not known whether TENS would help women to manage pain at home in early labour.
TENS has been proposed as a means of reducing pain in labour. The TENS unit emits low-voltage electrical impulses which vary in frequency and intensity. During labour, TENS electrodes are generally placed on the lower back, although TENS may be used to stimulate acupuncture points or other parts of the body. The physiological mechanisms whereby TENS relieves pain are uncertain. The TENS unit is frequently operated by women, which may increase sense of control in labour.
Review CD#: 
July, 2009
Authored by: 
Brian R McAvoy