Shaban et al. 2013

This study compares the use of TENS machine to Pethidine/Demerol (a pharmacological pain relief option used in hospitals), where it was found that TENS offered the same level of pain relief as this common drug...

Researchers in Egypt randomly assigned 100 people in active labour to either receive low-intensity TENS applied to the back, or to receive Pethidine/Demerol, which is an injectable narcotic. TENS was used in the experimental group until the participants reached 10 centimetres dilation.

They found a decrease in pain scores in both groups, but there was no significant difference between the groups. Forty-eight hours after the birth, the people who were randomly assigned to receive TENS during labor were much more satisfied with their birth, on average, compared to the people who received the injectable pain medication. Of those who received TENS, 83% reported being satisfied, compared with only 10% of those who received Demerol.

In addition to low satisfaction, the people who received Demerol also reported side effects such as drowsiness, nausea and vomiting. Babies in the Demerol group also had lower Apgar scores after birth. There were no bad side effects reported in the TENS group.