A therapy that eases pain by sending electrical pulses through the skin may be a reasonable option for managing the pain of childbirth, a new research review concludes.

There is only limited evidence that the therapy — called transcutaneous electrical nerve stimulation, or TENS — reduces labor pains, according to the review in the Cochrane Library, a publication of the Cochrane Collaboration, an international research organization.

But there is also no evidence that using TENS during childbirth poses any risks, researchers found in their review of 19 clinical trials.

Given the lack of harm to mothers and newborns, "we would therefore say that TENS is a personal choice," researcher Tina Lavender, of the University of Manchester School of Nursing in the UK, told Reuters Health.

TENS units are small, inexpensive devices that deliver low-voltage electrical currents through electrodes placed on the skin. It's thought that the therapy helps relieve pain by stimulating nerve pathways in the spinal cord, thereby disrupting the transmission of pain signals to the brain.

For their review, Lavender and her colleagues analyzed 19 clinical trials involving 1,671 women who were randomly assigned to either use a TENS unit during labor or stay with more-routine care.

In some studies, the TENS device was compared with an inactive, "placebo" device. And in most studies, women in the TENS group were free to request other analgesia as well.

In general, the review found that the women treated with TENS were less likely to report severe pain during labor. However, the evidence was not strong or consistent across the studies, according to Lavender and her colleagues.

In studies where TENS was used along with epidural pain medication, there was no evidence of an added benefit from the device.

Still, Lavender and her colleagues say, the evidence argues for making TENS available to women who are interested.

Some hospitals, at least in the UK, provide TENS machines to women in labor, Lavender said. But women can also rent or buy the small devices on their own, she noted.