This study compared the percentage of high pain scores from one group of people, measuring the scores before using a TENS and then 30 minutes after using a TENS...

Before using a TENS, 83% of people said their pain was a seven or higher

After using a TENS for only 30 minutes, only 20% of people said their pain was a seven or higher

Conclusion: TENS produces a significant decrease in pain during labour and postpones the need for pharmacological analgesia for pain relief.