Transcutaneous electrical nerve stimulation (TENS) for pain control during cervical dilator placement prior to dilation and evacuation: A randomized controlled trial

  • McCloskey, Leanne Rita (PD/PI)

Project: Research project

Project Details


Dilation and Evacuation is the most common method of second trimester abortion. Studies have shown that adequate cervical preparation is necessary for the procedure to be performed safely and reduce the risk of complications. However, in the majority of cases the placement of these dilators is done with minimal pain management options. Previous research has shown that paracervical block reduces pain with laminaria insertion, (Soon et al., 2017) however despite this, the placement of dilators continues to be, for many, the most painful part of the dilation and evacuation procedure. Several studies have been performed comparing cervical dilation techniques and rated dilator placement pain as moderate to severe (Mercier & Liberty, 2014). Pain following insertion in the hours leading up to the dilation and evacuation has been rated as less severe, but persistent. Transcutaneous electrical nerve stimulation (TENS) has been used in pain relief since 1965, when Melzack and Walls proposed using electrical stimulation as analgesia based on the gate control theory of pain relief (Johnson, Paley, Howe, & Sluka, 2015; Vance, Dailey, Rakel, & Sluka, 2014). TENS units are small, inexpensive, portable, battery-powered devices which deliver mild, alternating electrical currents via electrodes positioned on the skin near the anticipated dermatomal distribution of pain. The parameters of pulse frequency and pulse intensity are adjustable and linked to TENS efficacy (Vance et al., 2014). They overall have a favorable safety profile. Contraindications include electronic implants, such as cardiac pacemakers and implantable cardioverter defibrillators ("ELECTROPHYSICAL AGENTS - Contraindications And Precautions: An Evidence-Based Approach To Clinical Decision Making In Physical Therapy," 2010). Two main theories have been proposed regarding how TENS provides analgesia. According to the “gate control” theory, neuromodulation may activate large myelinated afferent nerve fibers in the dorsal horn to inhibit transmission in primary afferent nociceptive fibers. The inhibitory input from the large myelinated afferent fibers is thought to be able to “close the gate” to prevent transmission of pain sensation. (Johnson et al., 2015). The endorphin-mediated theory of pain relief states that a stimulus outside the central nervous system can raise the level of endogenous endorphins and therefore provide analgesia. (Vance et al., 2014)
Effective start/end date3/1/196/30/21


  • Society of Family Planning Research Fund (SFPRF19-14)


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