TRANSCUTANEOUS ELECTRICAL NERVE STIMULATION FOR PAIN RELIEF IN PRIMARY DYSMENORRHEA

ABSTRACT

This article reviews how transcutaneous electrical nerve stimulation (TENS) functions as a non-pharmacological treatment for primary dysmenorrhea. It explains the biophysical mechanisms of TENS analgesia (gate control, endogenous opioid release, and neuromodulation) and presents clinical evidence from recent RCTs that demonstrate its efficacy in reducing menstrual pain and medication use.

Keywords: transcutaneous electrical nerve stimulation, dysmenorrhea, pain modulation, gate control, endogenous opioids, nonpharmacologic therapy, neuromodulation, menstrual pain.

Primary dysmenorrhea, a highly prevalent gynecologic problem often described as cramping uterine pain during menstruation, affects a large proportion of reproductive-age women. It can present as intense pain that resists conventional treatment (such as NSAIDs), sometimes accompanied by nausea, headache, and functional impairment. When standard analgesics do not provide sufficient relief or are contraindicated, women seek alternative methods for pain relief.

One viable method is transcutaneous electrical nerve stimulation (TENS), which delivers electrical pulses via skin electrodes to modulate pain signals. TENS has been widely used for other acute and chronic pain conditions, and its application to dysmenorrhea is grounded in well-established biophysical mechanisms. Clinical trials and systematic reviews show that TENS significantly reduces menstrual pain intensity and analgesic consumption compared with placebo. Typical effective protocols use high-frequency (∼80–100 Hz) sensory-level stimulation for 20–40 minutes on the lower abdomen and/or back during menses. TENS’s safety profile is excellent, with only minor skin irritation being reported. In practice, TENS can be recommended as a first-line or adjunct therapy for dysmenorrhea, possibly lowering NSAID needs. Key research gaps include determining optimal stimulation parameters (such as frequency, duration, and intensity), evaluating long-term efficacy and safety, and conducting large randomized trials comparing TENS with standard pharmacological therapies. Further research is also needed to clarify its effects on quality of life and functional outcomes.

The biophysical mechanisms of TENS analgesia include the classical gate-control theory and activation of endogenous inhibitory pathways. In simple terms, high-frequency (∼80–100 Hz) TENS preferentially stimulates large-diameter A-beta sensory fibers in the skin. This stimulation “closes the gate” in the spinal cord dorsal horn, inhibiting the transmission of nociceptive (pain) signals from smaller A-delta and C fibers. In addition, TENS triggers the central nervous system to release endogenous opioids (such as endorphins, enkephalins), which then bind to opioid receptors and reduce pain sensation. TENS also engages descending pain-inhibitory pathways (serotonergic, noradrenergic) that further suppress spinal nociceptive transmission.

Recent clinical evidence supports the use of TENS for dysmenorrhea. A landmark randomized controlled trial by Guy et al. (2022) (double-blind crossover, n=40) showed that high-frequency TENS (preprogrammed device) applied to the abdomen/back for 30 minutes daily over 2–3 days of menstruation produced a 53% reduction in pain intensity, versus no effect in the sham group. Rapid relief occurred in 74% of participants within 20 minutes, lasting over 7 hours, and analgesic (NSAID) use fell by 93% in the TENS group. Another RCT (Camilo et al. 2023) used an “interactive” multi-channel TENS (35 min session) in 124 women and found highly significant pain reduction (p<0.001), with prolonged analgesia and much less need for pain medication compared to placebo. A recent analysis (Sindi et al. 2026) pooled 13 RCTs (779 women) and confirmed that TENS significantly lowers pain scores (mean VAS decrease ≈1.97 points, p=0.0009) and extends the duration of relief (standardized mean difference ≈0.78, p<10^-5). This analysis also found that women using TENS took on average 1.3 fewer Ibuprofen tablets per cycle than controls (MD≈−1.29 tablets, p=0.04). Important to mention that TENS reduced not only lower-abdominal pain along with referred pain to the back and thighs (large effect sizes, SMD 1.3–1.6, p<10^-5). Functional interference scores (Brief Pain Inventory) were unchanged, implying the need for more research on quality-of-life outcomes. Earlier systematic reviews (e.g., Arik et al., 2022) similarly reported strong analgesic benefits from both high- and low-frequency TENS in primary dysmenorrhea. A Cochrane review (2024) noted that the evidence is limited but suggests that HF and LF TENS may reduce pain relative to no treatment. Overall, high-quality trials and syntheses consistently indicate that TENS provides clinically meaningful pain relief in dysmenorrhea.

Effective TENS protocols in these studies generally involve sensory-level stimulation at a strong but comfortable intensity. Most trials used pulse frequencies of 80–100 Hz and pulse durations around 200–400 microseconds. Practitioners place 2–4 electrodes (pads) over the suprapubic/low-abdominal area, the sacral/lumbar region, or specific acupuncture-like points associated with uterine pain. Clinicians typically administer sessions lasting 20–45 minutes at the onset of menstrual pain, repeating them daily for the first 1–3 days of menstruation. For example, Guy et al. instructed women to self-administer TENS (nominally 100 Hz) for 30 minutes twice per day during menses. Camilo et al. used a single 35-minute session that produced lasting analgesia. Most practitioners recommend that patients increase the intensity to just below the motor threshold (a strong tingling sensation) during treatment to maximize the effect. Some studies suggest that higher intensities activate more afferent fibers and enhance analgesia. Researchers have used both conventional (constant) and “burst” or “modulated” TENS modes. However, no studies have established the clear superiority of one mode over another in dysmenorrhea.

Comparisons of TENS with other treatments suggest comparable efficacy and a key advantage in its side-effect profile. While head-to-head trials are few, the pain reduction from TENS is similar in magnitude to that of NSAIDs in several studies, without gastrointestinal or renal risks. One trial reported no significant difference between TENS and ibuprofen across several cycles (both reduced pain), but combining TENS with NSAID provided even better relief. Importantly, recent analytic data show that TENS might significantly reduce analgesic consumption, highlighting a drug-sparing effect. TENS has also been compared with other physical modalities (e.g., heat packs, exercise) in small trials, generally performing as well as the latter. Overall, TENS appears to be as effective as standard analgesic measures for immediate pain control, with the potential for fewer systemic adverse effects.

TENS is very safe when used for dysmenorrhea. It is noninvasive and has few side effects. Absolute contraindications include pregnancy (especially abdominal stimulation in labor), implanted electrical devices (pacemakers, deep brain stimulators), and active cancer over the stimulation site. Electrodes should not be placed over areas of broken skin or active infections. The most common adverse effect is minor skin irritation or allergic reaction to electrode gel/adhesive (reported in about 2–3% of users). This can be easily managed by using hypoallergenic pads or repositioning the electrodes. No serious adverse events have been reported in high-quality trials. Unlike opioids or NSAIDs, TENS carries no risk of general toxicity, overdose, or organ damage. Mild muscle twitching can occur if the intensity is set too high, but this is not harmful. Overall, TENS’s safety profile makes it suitable for home use under guidance, and it is notably useful for patients who cannot take medications (e.g., those with peptic ulcer or renal disease).

In practice, clinicians can recommend TENS as part of a comprehensive dysmenorrhea management plan. Based on the evidence, patients should be advised to start TENS at the first sign of menstrual cramps. The stimulation intensity should be as strong as tolerable without causing pain; studies indicate that inadequate intensity may reduce effectiveness. Electrode placement can be adjusted to the individual’s pain pattern, but commonly includes bilateral lower abdominal pads or paraspinal electrodes at L3–S1. Treatment sessions should last at least 20 minutes (often 30–40 min) and can be repeated two or three times per day as needed. To sustain benefit, TENS therapy is typically used during each menstruation until symptoms improve. Some guidelines suggest combining TENS with standard care: for example, women may use both TENS and NSAIDs concomitantly, which might allow lower drug doses. Follow-up must assess pain relief and any skin issues, adjusting the protocol if needed.

Table 1.

Key clinical studies and systematic reviews of TENS in primary dysmenorrhea.

Overall, evidence indicates that TENS serves as an effective and safe adjunct for relieving menstrual pain. It delivers rapid analgesia through well-understood neuromodulatory mechanisms, and high-quality trials demonstrate clinically significant pain reduction versus placebo. By reducing analgesic use and improving comfort, TENS can improve quality of life during menstruation. Researchers should focus future studies on large pragmatic trials that directly compare TENS to standard therapies, optimize treatment parameters, and evaluate long-term outcomes. The consistent findings so far support TENS as a valuable, non-drug option for women with primary dysmenorrhea.

References:

1. Guy M, Foucher C, Juhel C, et al. Transcutaneous electrical neurostimulation relieves primary dysmenorrhea: a randomized double-blind controlled trial. Prog Urol. 2022;32(7):487–497. DOI: 10.1016/j.purol.2022.01.005.
2. Camilo FM, Bossini PS, Driusso P, et al. Effects of electrode placement on analgesia using TENS for primary dysmenorrhea: a single-blind randomized controlled trial. Cureus. 2023;15(5):e39326. DOI: 10.7759/cureus. 39326.
3. Sindi H, Alzaher G, Almasad R, et al. Transcutaneous electrical nerve stimulation for treatment of primary dysmenorrhea: a systematic review and analysis of randomized controlled trials. Int J Med Dev Countries. 2026;51(1):1–11. DOI: 10.24911/IJMDC.51-1765701074.
4. Han S, Park KS, Lee H, et al. Transcutaneous electrical nerve stimulation (TENS) for pain control in women with primary dysmenorrhea. Cochrane Database Syst Rev. 2024;7:CD013331.
5. Physiopedia. Transcutaneous Electrical Nerve Stimulation (TENS). Physiopedia.
6. Johnson MI. Transcutaneous electrical nerve stimulation: mechanisms of action and clinical effectiveness. Phys Ther Rev. 2007;12(4):323–332. (Referenced in Physiopedia).
7. Camilo, Fabio &amp; Bossini, Paulo &amp; Driusso, Patricia &amp; Avila, Mariana &amp; Parizotto, Nivaldo &amp; Sousa, Ueverton &amp; Ramos, Rogério. (2023). The Effects of Electrode Placement on Analgesia Using Transcutaneous Electrical Nerve Stimulation for Primary Dysmenorrhea: A Single-Blind Randomized Controlled Clinical Trial. Cureus. 15. 10.7759/cureus.39326.
8. Sindi, Hala &amp; Alzaher, Ghadeer &amp; Almasad, Reema &amp; Altamimi, Lubna &amp; Alqahtani, Shatha &amp; Shubbar, Eman &amp; Alsaedi, Alanoud &amp; Alamri, Tulin &amp; Aljohani, Abdulaziz &amp; Alghamdi, Saja &amp; Alsaeed, Noor &amp; Alsayed, Rufaida. (2026). Transcutaneous electrical nerve stimulation for treatment of Primary dysmenorrhea: a systematic review and analysis of randomized controlled trials. International Journal of Medicine in Developing Countries. 51. 001-011. 10.24911/IJMDC.51-1765701074.
9. Beatriz García-García, María José Díaz-Arribas, María Alicia Urraca-Gesto, Juan Antonio Valera-Calero, Rosa María Ortiz-Gutiérrez, Gustavo Plaza-Manzano. Journal of Integrative and Complementary Medicine, Effectiveness of Radiofrequency in Primary Dysmenorrhea: A Randomized Controlled Trial, 2025, 11, 970