Analgesic Efficacy of Transcutaneous Electrical Nerve Stimulation (TENS) Versus Placebo During the First Stage of Labor

Study Overview
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Brief Summary
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This study seeks to verify the analgesic efficacy of TENS during the first stage of labor applying TENS parameters that, according to with the evidence, can be effective for this application and discarding the placebo effect according to the methodological recommendations.

Detailed Description
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TENS is a non-pharmacological alternative for pain control during labor. Although it's a method that has been used for decades, there is not enough evidence on its efficacy, so it's considered ineffective in the Spanish and British guidelines of clinical practice. The present study seeks to verify the analgesic efficacy of TENS by applying the electrodes in the spinal nerve roots associated with labor pain and using conventional TENS with parameters that, according to the evidence, may be effective for this application.

Official Title
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Analgesic Efficacy of Transcutaneous Electrical Nerve Stimulation (TENS) Versus Placebo During the First Stage of Labor. Double-blind Randomized Clinical Trial

Conditions
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Labor Pain, Transcutaneous Electric Nerve Stimulation

Intervention / Treatment
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* Device: TENS
* Device: TENS Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: - Women attending routinary fetal monitoring before labor Exclusion Criteria: Multiparous Scheduled cesarean Implantable Cardioverter Defibrillator (ICD) or pacemaker Epilepsy Fetal malformation Language barrier

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Intervention<br>TENS application using the TensMed S82 (Enraf Nonius). Current parameters: balanced symmetric biphasic square waveform, continuous stimulation, frequency 80 Hz, pulse duration modulated between 250 and 290 μs, modulation time 5 seconds. Self-adhesive electrodes of 50 x 90 mm applied paravertebrally to 2 cm. of the spinous apophysis. Use of two channels with independent intensity (mA): electrodes of the first channel applied at level T10-L1 and second channel ones at level S2-S4. Maximum intensity without reaching pain, increasing the intensity throughout the application to maintain this level. Start of the intervention when the woman expresses pain. End of the intervention when neuraxial anesthesia is applied (if the woman demands it) or after delivery. | Device: TENS<br>* TENS application using the TensMed S82 (Enraf Nonius). Current parameters: balanced symmetric biphasic square waveform, continuous stimulation, frequency 80 Hz, pulse duration modulated between 250 and 290 μs, modulation time 5 seconds. Self-adhesive electrodes of 50 x 90 mm applied paravertebrally to 2 cm. of the spinous apophysis. Use of two channels with independent intensity (mA): electrodes of the first channel applied at level T10-L1 and second channel ones at level S2-S4. Maximum intensity without reaching pain, increasing the intensity throughout the application to maintain this level. Start of the intervention when the woman expresses pain. End of the intervention when neuraxial anesthesia is applied (if the woman demands it) or after delivery.<br>|
| Placebo Comparator: Placebo<br>Same application as Intervention, but using 0,1 mA as fixed intensity on both channels. | Device: TENS Placebo<br>* Same application as Intervention, but using 0,1 mA as fixed intensity on both channels.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pain intensity measure | Self reported pain intensity. Score 0-10 (0 = no pain, 10 = pain as bad as can be), using a 0-10 pain scale combined with colored faces pain scale, for measuring the change of pain. | Start of intervention, each 30 minutes during intervention, end of intervention (when neuraxial anesthesia is applied -if the woman demands it- or after delivery, assessed up to 10 hours from intervention's start). | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| TENS satisfaction | Self reported interest on use of TENS on future deliveries. Score 0-10 (0 = no way, 10 = absolutely necessary) | At leaving the labor room, assessed up to 3 hours after delivery. |