TENS is the application of a very small electrical current to the skin to decrease the perception of pain elsewhere in the body. TENS has been used for surgical and chronic pain patients. The current prevents pain signals from reaching the brain, just like a gate not letting anything pass. In theory this may stimulates the body's production of higher levels of endorphins (natural painkillers).
electrode pads are placed on the lower back or suprapubic area (just below the bellybutton). These pads are connected to a small box, controlled by the mother, that controls the amount or frequency of electrical stimulus given. The small amount of electricity given by the box results in a nonpainful buzzing feeling (skin numbness) felt by the mother at the site of electrodes.
the effectiveness of TENS has been well studied in laboring women. There has been no reported change in the perception of pain or utilization of pain medications when compared to controls. However most women found TENS helpful perhaps due to the more active role the TENS unit gives the laboring mother in dealing with pain. TENS treatments have not been found to harm either mother or baby.
The above information was obtained from the following publications. If you would like more information on TENS we suggest reading the papers and discussing this with your obstetrician.
Eappen S, Robbins D., Nonpharmacological means of pain relief for labor and delivery, Int Anesthesiol Clini. 2002 Fall; 40(4): 103-14, Review
Simkin P.,Nonpharmacologic relief of pain during labor:Systematic reviews of five methods, Am J Obstet gynecol, 2002 Volume 186, Number 5 ,S131-159
Murray Enkin, A Guide to Effective Care in Pregnancy and Childbirth, 3rd Ed., Oxford University Press, 2000
(Thanks to Pulsar-tens for graphic)