Dong 2015.

Methods	3‐arm parallel randomised controlled trial of 180 women.
Participants	Women aged 20‐25, with a planned vaginal delivery, singleton pregnancy, 37‐42 weeks gestational age, fetus in vertex presentation, no obstetric or non‐obstetric complications, cervical dilation greater than or equal to 3 cm with regular contractions.
Interventions	2 experimental groups, 1 control: 1. EX‐B2, 2. SP6, 3. Control. An electro‐acupuncture device (HANS‐100B, China) provides electrical current with intensity range from 5 to 40 mA. The frequency of 100 Hz with a burst frequency of 2 Hz (dense‐dispersed waveform), pulse duration of 0.5 ms (ms) was used. In this study, the intensity of the current was set at 15 mA at the starting point of the active phase of labour and can be adjusted to higher intensity upon request. The device was run by experienced midwives who had been adequately trained in acupuncture before the study. 1. In EX‐B2 (Appointed Jiaji acupoints, approximately 1.7 cm lateral to the posterior median line, from tenth thoracic vertebral to third lumbar vertebral) group, 2 electrodes which connected to the device were attached on the bilateral EX‐B2 acupoints. 2. In SP6 (Sanyinjiao acupoints, 5 cm above medial malleolus in lower leg) group, 2 electrodes were attached on SP6 acupoints of both legs. 3. Routine intrapartum care
Outcomes	Primary: VAS: 0 cm to 10 cm scale. VAS scores were recorded during the last contraction before the intervention and then 30, 60, 120 minutes after the intervention in active phase of labour by the same trained midwife. VAS scores decreased > 3 at the last VAS measurement was considered effective. Secondary: duration of labour – active, second and third phases, oxytocin use, neonatal birthweight, Apgar scores 1 and 5 minutes.
Notes	Study duration: October 2012 to September 2013. Funding: not stated. Conflict of interest: authors state there is no conflicts of interest. Setting: maternity hospital. Country: China.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	By lottery method.
Allocation concealment (selection bias)	Unclear risk	Not reported.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants and clinician not blinded. Interventions were substantially different and obvious to an observer.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Outcomes assessor was treating clinician.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Describes attrition of participants.
Selective reporting (reporting bias)	Unclear risk	No study protocol available and limited study outcomes were reported.
Other bias	Unclear risk	Not sufficient information reported.