Transcutaneous Electrical Nerve Stimulation As A Pain-Relieving Approach in Labor Pain: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background: Transcutaneous electrical nerve stimulation (TENS) is a non-invasive electrophysical pain-relieving modality that also can be used in labor pain. Compared to other methods, TENS is not commonly practiced in intrapartum care due to a lack of knowledge about its clinical efficacy. Hence, a comprehensive overview of all types of randomized controlled trials (RCTs) on TENS can provide a better insight into this method and its efficacy in labor pain. Objectives: To perform a systematic review to assess the efficacy of TENS for labor pain control compared to other treatments. Search Strategy: PubMed, Cochrane Library, Embase, and Web of Science databases were searched for studies using keywords “TENS” combined with “labor pain” and “labor.”. Selection Criteria: Eligible criteria included RCTs, full-text studies, English, and Danish literature, whereas exclusion criteria included animal studies and abstracts. Data Extraction and Analysis: The selection of eligible items and assessment of methodological quality were performed independently by two researchers (KT and PG). A meta-analysis was performed to analyze the treatment effects on pain intensity reduction, additional analgesia, and satisfaction of TENS. Main Results: Twenty-six RCTs were included in this review involving a total of 3348 parturients. TENS showed significant efficacy in the reduction of pain intensity (pooled RR 1.52, 95% CI [1.35; 1.70]). Most of the studies had a high risk of bias, and the average grade of the studies indicated low quality. Conclusions: The forest plot showed a small, but statistically significant efficacy of TENS on the reduction of pain intensity. However, it is not clear if the results were affected by the poor quality of the studies. This systematic review is the first that shows the application of TENS has significant efficacy in lowering labor pain. Findings from this review encourage the application of qualified methods for future and prospective studies with TENS applied in labor pain.