Transcutaneous Electrical Nerve Stimulation (TENS) for Pain Management During Labor. (TENS-LABOR)

Transcutaneous Electrical Stimulation for Pain Reduction During Labor: A Crossover Clinical Trial.

This is a randomized, double-blind, crossover clinical trial to evaluate the efficacy of transcutaneous electrical nerve stimulation (TENS) as a non-pharmacological therapeutic intervention for reducing pain in women during the active phase of labor. Nulliparous women with term pregnancies will be randomly assigned to sequences involving TENS intervention and placebo (device off) periods, separated by a washout. The primary outcome is labor pain intensity measured by the Visual Analog Scale (VAS). Secondary outcomes include duration of the active labor phase, maternal and neonatal safety profile, and childbirth experience satisfaction. The study will be conducted at the Hospital Escuela Universitario from feb 2026 to Ago 2026.

Study Overview

• Status: Recruiting
• Conditions: Labor Pain
• Intervention / Treatment: Device: Transcutaneous Electrical Nerve Stimulation (TENS); TENSCARE Perfect Mama+ TENS unit; Device: Sham Comparator

Detailed Description

This is a prospective, randomized, double-blind, placebo-controlled, two-sequence, two-period crossover clinical trial. The study aims to evaluate the efficacy and safety of Transcutaneous Electrical Nerve Stimulation (TENS) as a non-pharmacological intervention for pain management during the active phase of first-stage labor.

The trial will be conducted in the Labor and Delivery Unit of the Maternal-Infant Block at Hospital Escuela Universitario in Tegucigalpa, Honduras. The unit is equipped with standard obstetric monitoring and care facilities.

Methodological Details:

Crossover Design: Each participant will act as her own control. Participants will be randomized to one of two sequences: 1) Active TENS followed by Sham TENS, or 2) Sham TENS followed by Active TENS.

Intervention & Control: The active intervention involves the use of a commercial, portable TENS unit (TENSCARE Perfect Mama+). The sham/placebo control involves the identical application of the device and electrodes but with the stimulator unit switched off. To maintain blinding, all devices will be visually identical and pre-coded by a third party not involved in data collection.

Washout Period: A standardized 30-minute washout period will be implemented between the active and sham phases. This duration is based on literature indicating the analgesic effects of TENS subside within 20-60 minutes post-use.

Intervention Periods: Each phase (active or sham) will have a defined application period during cervical dilation from ≥5 cm up to 10 cm. Pain assessments (Visual Analog Scale - VAS) will be conducted at baseline, 15 minutes, and 30 minutes after the initiation of each phase. The total duration of TENS/sham use per phase will be recorded.

Blinding Assessment: At the conclusion of the study, a blinding validation questionnaire will be administered to participants and clinical staff to assess the success of masking.

Additional Assessments: Beyond the crossover phases for pain measurement, the study will continue to observe participants in the experimental group to collect secondary data on the total duration of active labor, mode of delivery, maternal and neonatal complications, and postpartum satisfaction (using the Mackey Satisfaction Childbirth Rating Scale - MCSRS) within 24 hours after birth.

Statistical Considerations: The primary analysis will use linear mixed models or repeated measures ANOVA, accounting for treatment, period, and sequence effects. Carry-over effects will be specifically tested. The intention-to-treat (ITT) and per-protocol (PP) populations will be defined for analysis.

Scientific Rationale: The study design (crossover) increases statistical power and controls for inter-individual variability in pain perception. The double-blind, placebo-controlled approach minimizes bias. The protocol includes specific measures for bias minimization: centralized computerized randomization via REDCap, allocation concealment, and blinded outcome assessment.

Note: The full study protocol contains additional details on sample size calculation (n=132, based on a 1.0-point difference on VAS), safety monitoring, adverse event reporting, data management in REDCap, and ethical oversight by the Institutional Review Board of the Faculty of Medical Sciences, National Autonomous University of Honduras (UNAH).

• Study Type: Interventional
• Enrollment (Estimated): 132
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Ricardo A. Gutierrez Ramirez, MD, MSc; Phone Number: +50497546940; Email: ricardo.gutierrez@unah.edu.hn
• Study Contact Backup: Name: Sara J. Sevilla Ardon, MD; Phone Number: 504 99706157; Email: docencia.investigacion2012@gmail.com

Study Locations

• Honduras
  • Francisco Morazán Department
    • Tegucigalpa, Francisco Morazán Department, Honduras, 11101
      • Recruiting
      • Hospital Escuela
      • Contact: Ricardo Arturo Gutierrez Ramirez, MD, MSc.; Phone Number: 50497546940; Email: ricardo.gutierrez@unah.edu.hn
      • Contact: Sara J Sevilla Ardon, MD; Phone Number: 50499706157; Email: docencia.investigacion2012@gmail.com
    • Tegucigalpa, Francisco Morazán Department, Honduras, 11101
      • Recruiting
      • Instituto Hondureño de Seguridad Social
      • Contact: Sara J Sevilla Ardon, MD; Phone Number: 50499706157; Email: docencia.investigacion2012@gmail.com
      • Principal Investigator: Cristhian O Sandoval Alfaro, MD
      • Principal Investigator: Jorge L Turcios Varela, MD
      • Principal Investigator: Sara J Sevilla Ardon, MD
      • Principal Investigator: Maynor E Rodriguez Burgos, MD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Signed informed consent.
• Women aged 18-45 years.
• Nulliparous.
• Term singleton pregnancy (37-42 weeks).
• Cephalic presentation.
• Spontaneous onset of labor or induced/conducted labor under adequate control.
• Cervical dilation of at least 5 cm at enrollment.
• Normal amniotic fluid volume and reassuring fetal monitoring.
• Uncomplicated pregnancy.

Exclusion Criteria:

• Multiple pregnancy.
• Non-cephalic presentation.
• Severe obstetric complications (e.g., preeclampsia, placental abruption).
• Maternal chronic or acute diseases interfering with safety.
• History of neurological/psychiatric disorders contraindicating TENS.
• Abnormal fetal monitoring or amniotic fluid.
• Pre-pregnancy BMI >30 kg/m².
• Fetal demise.
• Illiteracy.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Active TENS Intervention; Participants receive transcutaneous electrical nerve stimulation (TENS) using the TENSCARE Perfect Mama+ unit. Electrodes are placed on the thoracolumbar region. The device is used for periods of 30-50 minutes every two hours during the active phase of labor (cervical dilation >=5 cm), or more frequently if desired by the participant.	Device: Transcutaneous Electrical Nerve Stimulation (TENS); TENSCARE Perfect Mama+ TENS unit; A portable, dual-channel TENS unit (TENSCARE Perfect Mama+) delivering low to moderate intensity electrical currents via skin surface electrodes placed on the thoracolumbar region. It has three preset programs, 50-60 intensity levels, a BOOST button for contractions, and an open-circuit safety feature. Used for non-pharmacological labor pain relief.
Sham Comparator: Sham/Placebo TENS; Participants undergo the same procedure with the TENS unit placed and electrodes attached, but the device remains switched off (no electrical stimulation is delivered)	Device: Sham Comparator; Participants undergo the identical procedure with the TENS unit placed and electrodes attached in the same position, but the device remains switched off (no electrical stimulation is delivered).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Labor Pain Intensity	Pain intensity during contractions, measured using the Visual Analog Scale (VAS).	Assessed at baseline (upon enrollment at >=5 cm dilation), at 15 minutes, and at 30 minutes after the start of each intervention phase (Active TENS or Sham) during the active phase of labor.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Duration of Active Labor Phase	Time elapsed from cervical dilation of 5 cm until complete cervical dilation (10 cm).	From study intervention start (>=5 cm) until delivery of the baby (up to 24 hours).
Maternal Satisfaction with Childbirth Experience	Satisfaction is measured using the validated Mackey Childbirth Satisfaction Rating Scale (MCSRS). This 35-item questionnaire uses a 5-point Likert scale (1 = Very Dissatisfied to 5 = Very Satisfied). The total score ranges from 35 to 175. A baseline score indicating satisfaction is considered to be ≥140 points (corresponding to an average rating of 4 or "Satisfied" across all items). Higher scores represent greater satisfaction with the childbirth experience. The scale assesses multiple dimensions including satisfaction with: the obstetrician, nursing staff, the newborn, the dilation phase, the expulsive phase, and overall comfort.	Assessed once within the first 24 hours postpartum (during the immediate puerperium, before hospital discharge).

Collaborators and Investigators

• Sponsor: Ricardo A Gutierrez Ramirez, MD, MSc, FACOG

Publications and helpful links

General Publications

• Ge Z, He J, Zhang P, Zhao W, Zhu G, Zhang J, Song Z, Cui J, Jiang X, Yu W. Clinical Outcomes and Radiologic Parameters of Endoscopic Lumbar Interbody Fusion Using a Novel Nerve Baffle with a Minimum 1-year Follow-up. World Neurosurg. 2023 Aug;176:e181-e189. doi: 10.1016/j.wneu.2023.05.025. Epub 2023 May 12.

Study record dates

Study Major Dates

• Study Start (Estimated): February 15, 2026
• Primary Completion (Estimated): August 31, 2026
• Study Completion (Estimated): September 15, 2026

Study Registration Dates

• First Submitted: February 3, 2026
• First Submitted That Met QC Criteria: February 3, 2026
• First Posted (Actual): February 10, 2026

Study Record Updates

• Last Update Posted (Actual): February 13, 2026
• Last Update Submitted That Met QC Criteria: February 10, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Analgesia; labor pain; Transcutaneous Electric Nerve Stimulation; Pain Management; Natural Childbirth
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Nervous System Diseases; Neurobehavioral Manifestations; Perceptual Disorders; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Labor Pain; Agnosia; Therapeutics; Physical Therapy Modalities; Rehabilitation; Anesthesia and Analgesia; Electric Stimulation Therapy; Analgesia; Transcutaneous Electric Nerve Stimulation
• Other Study ID Numbers: PGO-UNAH-49-3-2026

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: It is not yet known if there will be a plan to make individual participant data (IPD) available. The final decision will depend on the specific requirements of the target publication journal, further consultation with the local ethics committee regarding data sharing agreements, and a thorough assessment of our capacity to properly anonymize the data while preserving its scientific value for secondary analysis.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No