You will be provided with the titles and abstracts of a collection of medical RCT reports studying a clinical question -- for instance, the efficacy of an intervention on some medical outcome. Please write a few sentences synthesizing the findings of these reports, which could serve as a conclusion section for a systematic review article. Your response should not include any other text. The RCT reports are below.



Title 1:
Transcutaneous electrical nerve stimulation (TENS) for the treatment of primary dysmenorrhea: a randomized crossover comparison with placebo TENS and ibuprofen.
Abstract 1:
In a randomized four-way crossover study, 32 women with primary dysmenorrhea were treated with transcutaneous electrical nerve stimulation (TENS) for two cycles, placebo (sham) TENS for one cycle, or ibuprofen 400 mg four times a day for one cycle. The TENS setting used was 100 pulses per second with 100-microsecond pulse widths. The subjects were allowed to adjust the amplitude to a comfortable level. The pain rescue medication was ibuprofen 400 mg as needed, up to 1600 mg/day. Significantly more subjects who had TENS treatment did not require rescue medication or required less backup ibuprofen at 0-4, 4-8, and 8-12 hours after the onset of dysmenorrhea and starting treatment, as well as during the first 24 hours and for the duration of the menstrual flow, when compared with placebo TENS or ibuprofen-treated cycles (Tukey multiple comparison, P less than .01). Transcutaneous electrical nerve stimulation significantly delayed the need for ibuprofen by an average of 5.9 hours, compared with 0.7 hours when using ibuprofen alone (P less than .05, paired t test). Transcutaneous electrical nerve stimulation alone provided good to excellent subjective pain relief in 42.4% of subjects, compared with 3.2% with placebo TENS, and significantly reduced diarrhea, menstrual flow, clot formation, and fatigue compared with placebo TENS. Transcutaneous electrical nerve stimulation plus less ibuprofen provided pain relief equivalent to that obtained with ibuprofen alone (71 and 75% of the subjects, respectively). We conclude that TENS is a safe, effective, non-medication method for managing primary dysmenorrhea and that TENS plus ibuprofen was the best overall treatment, as indicated by pain relief.


Title 2:
Transcutaneous electrical nerve stimulation in the relief of primary dysmenorrhea.
Abstract 2:
The purpose of this study was to replicate a previous study to determine the effectiveness of acupuncture-like transcutaneous electrical nerve stimulation in treating primary dysmenorrhea. Twenty-one women with dysmenorrhea received a placebo pill or 30 minutes of acupuncture-like TENS. All subjects completed two pain questionnaires before treatment; immediately posttreatment; 30, 60, 120, and 180 minutes posttreatment; and the next morning upon awakening. Each woman also participated in a separate study measuring electrical resistance at four auricular acupuncture points before and immediately after treatment. The data were analyzed with a two-factor repeated-measures analysis of variance, which revealed statistical significance over time but not for group or interaction between group and time. Results revealed an average pain relief of at least 50% immediately posttreatment, indicating that acupuncture-like TENS may be useful for dysmenorrheic pain. This study also suggests that auriculotherapy via acupressure may relieve the pain of primary dysmenorrhea.


Title 3:
[TENS is effective in painful menstruation].
Abstract 3:
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Title 4:
Relief of primary dysmenorrhea by transcutaneous electrical nerve stimulation.
Abstract 4:
In this study we describe the use of high-frequency transcutaneous electrical nerve stimulation (TENS) (100 Hz) and low-frequency TENS (lf-TENS) (2 Hz trains) as compared with placebo-TENS (p-TENS) in a group of 21 patients suffering from primary dysmenorrhea. Naloxone, a relatively pure opiate antagonist, was an additional test administered to 6 volunteer patients who had experienced an alleviation of pain with TENS. As will be seen, 14 out of 21 patients receiving high-frequency TENS (hf-TENS) experienced a pain reduction exceeding 50% of its original intensity. During lf-TENS or p-TENS, only 7 and 5 patients, respectively, obtained pain relief exceeding 50%. In 4 out of 6 volunteer patients, the relief of pain obtained with lf-TENS was counteracted by naloxone, whereas the relief experienced with hf-TENS in the same patients was, in general, unaffected by naloxone.
High-frequency TENS was found to be effective for the treatment of dysmenorrhoea by a number of small trials. The minor adverse effects reported in one trial require further investigation. There is insufficient evidence to determine the effectiveness of low-frequency TENS in reducing dysmenorrhoea.