Intervention types			Detailed descriptions
Low-frequency pulsed electrotherapy or TENS^a (T)			Preprocedure preparation: The midwife will prepare the TENS device, electrodes, and connecting wires. The laboring woman will be positioned comfortably, and the skin will be cleansed with warm water. Procedure: Electrodes will be placed on the Hegu (LI4) point, Neiguan (PC6) point, T10-L1, and S2-S4 (Figure 2). The device will be set to alternate between frequencies of 2 Hz and 100 Hz every 6 seconds, with pulse widths of 0.6 ms for 2 Hz and 0.2 ms for 100 Hz. The intensity will be gradually increased from low to high based on the laboring woman's feedback until the optimal stimulation level is achieved. Typically, the intensity for channel 1 (Hegu and Neiguan points) will be set between 6 and 15 mA, while for channel 2 (T10-L1 and S2-S4), it will range from 6 to 40 mA. The midwife will instruct the laboring woman on how to adjust the intensity, empowering her to modify the settings according to her comfort level. Timing of application: TENS therapy will commence at the onset of contractions, with intensity increased during contractions and decreased during periods of relief. This therapy will continue as tolerated until the delivery of the placental. Postprocedure care: Upon completion of the treatment, the device will be turned off, electrodes will be removed, and the skin will be inspected for any signs of irritation. The area will be cleansed to ensure hygiene is maintained.
Acupoint stimulation (A)
	Auricular seed acupressure	Preprocedure preparation: The midwife will prepare a treatment tray containing a kidney dish, 75% alcohol swabs, and vaccaria seeds (Wang-Bu-Liu-Xing) with adhesive tape, tweezers, and a probe. The laboring woman will be positioned comfortably in a sitting, supine, or lateral position to ensure full exposure of the ear. Procedure: The midwife will stabilize the auricle and use a probe to identify the positive reaction points at the bilateral Uterus (TF2), ShenMen (TF4), Endocrine (CO18), Sympathesis (AH6a), and Subcortex (AT4) points (Figure 3). After disinfecting the ear with an alcohol swab, the midwife will apply vaccaria seeds with adhesive tape onto the selected acupoints and press them for 1-2 min per side to enhance stimulation. Timing of application: The procedure will be performed at the onset of contractions. The seeds should be pressed for 1-2 min per contraction or as tolerated until placental delivery. Postprocedure care: The seeds can remain in place for up to 1-2 days post delivery to alleviate uterine contraction pain. If the laboring woman experiences discomfort or requests removal, the procedure should be terminated immediately. After removal, the midwife should clean the auricle, ensure patient comfort, and adjust clothing and bedding.
	Acupressure	Preprocedure preparation: The midwife should encourage the woman in labor to empty her bladder and bowels, ensure a comfortable position, and maintain warmth. Procedure: During the latent phase of labor, due to the slow cervical dilation, abdominal pain tends to concentrate around the GuanYuan (CV4) point. The midwife can provide a massage using the palm of her right hand in a clockwise direction. Simultaneously, the left thumb can be used to apply pressure to the HeGu (LI4), NeiGuan (PC6), and KunLun (BL60) points (Figure 4). In the active phase of labor, the woman will be advised to adopt a left lateral position with the ZhongJi (RN3) point as the center. Pillows and cushions can be used to support the woman’s head and upper thigh. The midwife will use clockwise abdominal massage and apply pressure to the HeGu (LI4), SanYinJiao (SP6), TaiChong (LR3), and ZuSanLi (ST36) points. For back pain, focusing on the CiLiao (BL32) points, the woman should lean forward against a wall or support herself on the edge of the bed to minimize fetal weight on the spine. The midwife will provide a massage to the lumbar and sacral regions, as well as the back, including the ShenYu (BL23) points, and perform a circular massage around the buttocks with the HuanTiao (GB30) point as the center (Figure 5). Timing of application: Acupoint massage should begin at the onset of contractions and be paused during periods of relief. It may continue as tolerated until placental delivery. Postprocedure care: If the laboring woman experiences discomfort or requests termination, the procedure should be stopped immediately. The midwife should cleanse the skin, adjust the woman’s clothing, and ensure her comfort.
Combination of TENS and acupoint stimulation (T&A)			Preprocedure preparation: The midwife will prepare all necessary tools, including TENS equipment, Vaccaria seeds, alcohol swabs, tweezers, and a probe. The laboring woman will be positioned comfortably to ensure relaxation. Procedure: Initially, the midwife will apply auricular acupressure and place the TENS electrodes. During contractions, the laboring woman will be encouraged to massage the auricular acupoints, adjust the TENS intensity, and receive an acupoint massage. When experiencing contraction relief, the acupoint massage should be paused, allowing the laboring woman to adjust the TENS settings as needed. This intervention may continue as tolerated until placental delivery. Timing of application: This combined approach may be sustained as tolerated until placental delivery. Postprocedure care: If discomfort occurs, adjustments to the technique should be made, or it should be discontinued. The midwife should turn off and remove the TENS device, inspect the skin, and cleanse the area. Auricular acupressure may be continued for 1-2 days post delivery unless discomfort arises.