Effectiveness of transcutaneous electric nerve stimulator for pain relief in labour.

The effectiveness of transcutaneous electric nerve stimulation (TENS) for pain relief in labour was compared to inhalation analgesia consisting of 50% nitrous oxide and 50% oxygen (ENTONOX). In the first part of the study 101 patients in early labour were allocated to using TENS (Group A) or ENTONOX (Group B) for pain relief. Our results did not show any beneficial effect on pain relief in labour with the use of TENS over ENTONOX; 18.8% of patients in Group A went through labour without any further form of analgesia as opposed to 17.0% in Group B. In the second part of the study 20 nulliparous patients having induced labour were randomly allocated to use TENS (Group C) or ENTONOX (Group D) as the first modality of pain relief. A switchover was made when labour pains were no longer tolerable. The results showed that both TENS and ENTONOX could be used in early labour up to 5-6 cm cervical dilatation till the frequency of contractions was nearly 5 in 10 min or the first 3-4 hr from the time patients first requested pain relief in labour when frequency of contractions was nearly 4 in 10 min. TENS could be used in early labour for patients who wish to be ambulant and is as effective as ENTONOX. Either modality of pain relief was not adequate for pain relief throughout labour.