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Transcutaneous Electrical Nerve Stimulation for Pain Control During First-trimester Abortion

Transcutaneous Electrical Nerve Stimulation for Pain Control During First Trimester Abortion: a Blinded Randomized Controlled Trial

Status
Completed
Phases
NA
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT05320432
Acronym
TENS 2 0
Enrollment
70
Registered
2022-04-11
Start date
2023-01-20
Completion date
2024-03-21
Last updated
2025-02-25

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Abortion in First Trimester, Pain

Brief summary

First-trimester abortion aspiration procedures are painful and sedation is typically provided. It is unsafe to drive after sedation due to the prolonged motor delay from some anesthetic agents. Without a known escort, most clinics do not allow patients to use public transportation, taxis, or rideshare services. Arranging a ride may be harder for those seeking abortion care than other surgical procedures given privacy concerns and the need to travel far distances. Additionally, some people have medical reasons that makes sedation in an outpatient abortion clinic unsafe. As abortion restrictions increase and more people need to travel far distances to access care, it is important to investigate non-pharmacologic pain control options. Transcutaneous electrical nerve stimulation (TENS) delivers a low-level electrical current through the skin. By activating the descending inhibitory systems in the central nervous system, these pulses of electrical current reduce sensitivity to pain. TENS has been shown to be effective in decreasing pain with menstrual cramps and during medication abortion, and it was found to be non-inferior to IV sedation for first-trimester procedural abortion. However, it remains unclear if TENS is better than ibuprofen and local anesthesia via paracervical block alone. The overarching goal of this research is to identify an inexpensive, non-pharmacologic, alternative pain control strategy for those with a medical or social contraindication to IV sedation. The specific aim of this project is to evaluate the efficacy of TENS to prevent pain during first-trimester procedural abortion. To achieve this objective, a blinded, randomized superiority trial comparing the use of TENS to sham for management of pain during first-trimester aspiration abortion is proposed. This research is significant because the validation of a non-pharmacologic pain management technique would decrease barriers to accessing abortion care.

Detailed description

Abortion is common: one in four individuals will seek this care during their reproductive lifetime. Most abortions occur in the first trimester and nearly all - greater than 95% - occur in the outpatient clinic setting. Uterine aspiration is painful; most patients desire additional analgesia beyond local anesthesia. However, not every patient is a candidate for office sedation since multiple medical conditions are a contraindication and patients must have a ride home. The prolonged motor delay from some anesthetic agents makes driving after sedation unsafe. Without a known escort to monitor for surgical and anesthetic complications as recommended by the American Society of Anesthesia, most clinics do not allow patients to use public transportation, taxis, or rideshare services. Arranging a ride may be harder for those seeking abortion care than other surgical procedures given privacy concerns and the need to travel far distances. As abortion restrictions increase and more people need to travel far distances to access care, it is important to investigate non-pharmacologic pain control options. Transcutaneous electrical nerve stimulation (TENS) delivers an electrical current through the skin to activate the descending inhibitory systems in the central nervous system, effectively reducing sensitivity to pain. A previous trial comparing TENS to IV sedation found similar postoperative pain scores with a significantly shorter recovery time in the TENS group; however, this study did not evaluate or report intraoperative pain scores. It was found in a randomized controlled trial comparing TENS to IV sedation (in conjunction with local anesthesia) for first-trimester surgical abortion and that TENS had non-inferior pain scores to IV sedation and was considered an acceptable modality for pain control among participants. Through this proposed double blinded randomized controlled trial, it is hoped to demonstrate that TENS is a superior, non-invasive alternative pain control option for people undergoing surgical abortion in the first trimester who otherwise are not eligible for or decline IV sedation. Ultimately, the hope is to identify an inexpensive, alternative, non-pharmacologic pain control strategy for those with a medical or social contraindication to IV sedation in an effort to decrease barriers to accessing abortion care.

Interventions

DEVICETranscutaneous electrical nerve stimulation (TENS)

A low-level electrical current through the skin activates the descending inhibitory systems in the central nervous system.

DEVICESham

No current applied through pads.

Sponsors

Stanford University
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
SUPPORTIVE_CARE
Masking
TRIPLE (Subject, Caregiver, Outcomes Assessor)

Eligibility

Sex/Gender
FEMALE
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* 18 years old or older * English- or Spanish-fluency * \<12 weeks gestation * Presenting for aspiration abortion

Exclusion criteria

* Planned use of oral or IV sedation * Contraindications to office-based procedure as determined by attending physician * Fetal demise * Requiring pre-procedure use of misoprostol * Contraindication to TENS units use (pacemaker or epilepsy)

Design outcomes

Primary

MeasureTime frameDescription
Pain During Cervical DilationIntra-operative, collected during procedure (up to 30 seconds)Pain with manual cervical dilation, assessed by visual analog scale (VAS, 0-100mm; 0 being no pain and 100 being worst pain imaginable)

Secondary

MeasureTime frameDescription
Overall ExperiencePost-operative, collected following procedure (up to 20 minutes)Patient experience assessed by visual analog scale (VAS, 0-100mm; 0 being worst experience possible and 100 being best experience possible)
Procedure Timeup to 20 minutes
Pain During ProcedureIntra-operative, collected during procedure (up to 30 seconds)Pain during aspiration assessed by visual analog scale (VAS, 0-100mm; 0 being no pain and 100 being worst pain imaginable)
Time Spent in Recoveryup to 1 hour
Number of Participants Who Correctly Identified Whether They Received TENS or ShamPost-operative, collected after procedure (up to 30 seconds)This outcome is to measure the participant's perceived group allocation.
Provider Perceived Ease of ProcedurePost-operative, collected after procedure (up to 30 seconds)Provider experience assessed by visual analog scale (VAS, 0-100mm; 0 being easiest to use and 100 being most difficult to use)

Countries

United States

Participant flow

Participants by arm

ArmCount
Transcutaneous Electrical Nerve Stimulation (TENS)
Prior to the procedure, the patient will have two sets of two self-adhesive electrodes placed parallel to the spinal cord at the T10-L1 and S2-S4 levels for TENS administration. For participants randomized to the experimental group, the non-blinded study coordinator will turn on the TENS unit 5 minutes prior to the procedure and monitor stimulating frequency level (80-100 Hz and pulse duration of 400 microseconds; intensity or frequency will be monitored to be administered to a non-painful level). Transcutaneous electrical nerve stimulation (TENS): A low-level electrical current through the skin activates the descending inhibitory systems in the central nervous system.
35
Sham
For the participants randomized to sham, the same placement of electrodes will occur, but the unit will not be delivering electrical stimulation. Sham: No current applied through pads.
35
Total70

Withdrawals & dropouts

PeriodReasonFG000FG001
Overall StudyWithdrawal by Subject02

Baseline characteristics

CharacteristicTranscutaneous Electrical Nerve Stimulation (TENS)ShamTotal
Age, Continuous30.6 years
STANDARD_DEVIATION 6.5
29.9 years
STANDARD_DEVIATION 7.7
30.2 years
STANDARD_DEVIATION 7.1
Nulliparous11 Participants14 Participants25 Participants
Race (NIH/OMB)
American Indian or Alaska Native
1 Participants1 Participants2 Participants
Race (NIH/OMB)
Asian
9 Participants4 Participants13 Participants
Race (NIH/OMB)
Black or African American
2 Participants2 Participants4 Participants
Race (NIH/OMB)
More than one race
0 Participants5 Participants5 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants0 Participants0 Participants
Race (NIH/OMB)
Unknown or Not Reported
6 Participants3 Participants9 Participants
Race (NIH/OMB)
White
17 Participants20 Participants37 Participants
Region of Enrollment
United States
35 Participants35 Participants70 Participants
Sex: Female, Male
Female
35 Participants35 Participants70 Participants
Sex: Female, Male
Male
0 Participants0 Participants0 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
deaths
Total, all-cause mortality
0 / 350 / 35
other
Total, other adverse events
0 / 350 / 35
serious
Total, serious adverse events
0 / 350 / 35

Outcome results

Primary

Pain During Cervical Dilation

Pain with manual cervical dilation, assessed by visual analog scale (VAS, 0-100mm; 0 being no pain and 100 being worst pain imaginable)

Time frame: Intra-operative, collected during procedure (up to 30 seconds)

Population: Two excluded from sham as did not complete procedure.

ArmMeasureValue (MEDIAN)
Transcutaneous Electrical Nerve Stimulation (TENS)Pain During Cervical Dilation44 millimeters on VAS
ShamPain During Cervical Dilation50 millimeters on VAS
Secondary

Number of Participants Who Correctly Identified Whether They Received TENS or Sham

This outcome is to measure the participant's perceived group allocation.

Time frame: Post-operative, collected after procedure (up to 30 seconds)

Population: Two participants excluded from sham - did not complete procedure

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Transcutaneous Electrical Nerve Stimulation (TENS)Number of Participants Who Correctly Identified Whether They Received TENS or Sham32 Participants
ShamNumber of Participants Who Correctly Identified Whether They Received TENS or Sham21 Participants
Secondary

Overall Experience

Patient experience assessed by visual analog scale (VAS, 0-100mm; 0 being worst experience possible and 100 being best experience possible)

Time frame: Post-operative, collected following procedure (up to 20 minutes)

Population: Two excluded from sham - did not complete procedure

ArmMeasureValue (MEDIAN)
Transcutaneous Electrical Nerve Stimulation (TENS)Overall Experience75 millimeters on VAS
ShamOverall Experience62 millimeters on VAS
Secondary

Pain During Procedure

Pain during aspiration assessed by visual analog scale (VAS, 0-100mm; 0 being no pain and 100 being worst pain imaginable)

Time frame: Intra-operative, collected during procedure (up to 30 seconds)

Population: Two participants excluded from sham - did not complete procedure

ArmMeasureValue (MEDIAN)
Transcutaneous Electrical Nerve Stimulation (TENS)Pain During Procedure44 millimeters on VAS
ShamPain During Procedure56 millimeters on VAS
Secondary

Procedure Time

Time frame: up to 20 minutes

Population: Two excluded from sham - did not complete procedure

ArmMeasureValue (MEAN)Dispersion
Transcutaneous Electrical Nerve Stimulation (TENS)Procedure Time7.3 minutesStandard Deviation 2.9
ShamProcedure Time8.4 minutesStandard Deviation 4.1
Secondary

Provider Perceived Ease of Procedure

Provider experience assessed by visual analog scale (VAS, 0-100mm; 0 being easiest to use and 100 being most difficult to use)

Time frame: Post-operative, collected after procedure (up to 30 seconds)

Population: Two excluded from sham - did not complete procedure

ArmMeasureValue (MEDIAN)
Transcutaneous Electrical Nerve Stimulation (TENS)Provider Perceived Ease of Procedure16 score on a scale
ShamProvider Perceived Ease of Procedure15 score on a scale
Secondary

Time Spent in Recovery

Time frame: up to 1 hour

Population: Two excluded from sham - did not complete procedure

ArmMeasureValue (MEAN)Dispersion
Transcutaneous Electrical Nerve Stimulation (TENS)Time Spent in Recovery25.4 minutesStandard Deviation 8.8
ShamTime Spent in Recovery24.0 minutesStandard Deviation 10.8

Source: ClinicalTrials.gov · Data processed: Feb 5, 2026