- Pregnant women: Women who are known to be pregnant will not be recruited into the study. A pregnancy test will be administered to females prior to enrollment in TENS (or sham) treatment. Women who become pregnant before or during the 8-week TENS treatment period will be discontinued from the study. Women who become pregnant after the 8-week TENS treatment portion of the study will continue to be enrolled, and followed according to protocol guidelines (no information will be collected specifically on the pregnancy or fetus).