Investigation of varying frequencies of transcutaneous electrical nerve stimulation for labor pain control: a...

Transcutaneous electrical nerve stimulation (TENS) is an electrophysical non-invasive modality widely used for non-pharmacological pain management in several pain conditions, including labor pain. However, the efficacy of TENS in labor pain is yet not determined. Therefore, this study aimed to investigate the efficacy of TENS compared to sham in labor pain and examine the effective set of varying frequencies.

A double-blinded randomized sham-controlled pilot study was conducted in the labor ward at the Department of Obstetrics and Gynecology, Gødstrup Hospital, Herning Denmark. Healthy low-risk pregnant women admitted for childbirth at term were recruited and randomized to receive one of three types of TENS stimulation for 30 min; TENS1, which varied from low to high frequencies (4/100 Hz), TENS2 with high frequencies (80/100 Hz), and sham-TENS.

Of 23 women eligible, 12 women agreed to participate. No efficacy of any type of varied frequencies in TENS compared to sham-TENS was shown. However, TENS1 showed a non-significant reduction in visual analogue scale (VAS) compared to sham with 1.9 ± 3.4 cm at 10 min and 1.0 ± 2.5 cm at 30 min. Further, pain pressure threshold (PPT) showed a slight increase in sensitivity for TENS1 with 18.2 ± 58.7 kPa from baseline to 10 min. This may suggest a short-term efficacy of 10 min of TENS.

Our findings suggest that a main study with a proper sample size based on this study investigating TENS1 may reveal if this set of frequencies reduces pain in laboring women.Clinical Relevance - This study suggests relevance of considering non-pharmacologic and neuromodulating approach in labor pain management.