TENS stands for Transcutaneous Electrical Nerve Stimulation. It is a drug free, safe, non-invasive method of controlling pain. Mild electrical impulses pass through the skin and into the nerve fibers. This produces a tingling sensation.
How does TENS relieve pain?
It is believed that TENS works in two ways during labor. First, the impulses encourage your body to produce endorphins, the body's own way to combat pain. The second way is explained by the Gate Control Theory. In it's most basic terms, this happens when pain signal traveling to the brain are interrupted by some other stimuli.