Huang 2008.

Methods	Single‐blind randomised controlled trial, 4‐arm study: 1) electro‐acupuncture group N = 82; TENS group N = 82; control group (breathing) N = 81; spinal‐epidural analgesia group N = 79. Unit of randomisation: 1:1:1:1.
Participants	Inclusion criteria: 324 primiparae women aged 22‐34 years, vaginal delivery, monocyesis, not cephalopelvic disproportion, no abnormal fetal position, no serious complications of pregnancy, agreement to labour analgesia. Exclusion criteria: not explicitly stated.
Interventions	1) Electro‐acupuncture. Shi diagnosis labour pain mainly located in the lumbosacral and with bearing‐down sensation, sturdy body, desiring cold and fearing of warmth, good appetite, normal or dry stool, normal or less yellow urine, good sleep, normal red tongue with thin and whitish or slightly thicker tongue coating, wiry, drooling and strong pulse. Xu diagnosis: labour pain mainly located in the lower abdomen and distending, weak body, seeking warmth and fearing of cold, poor appetite, loose stool, clear abundant urine, increased nocturnal enuresis, worse sleep, easily waken up in the night, fatty and whitish tongue with teeth mark, thicken and greasy coating, deep and thin, weak pulse.  Electro‐acupuncture group applied self‐developed acusector on selected acupoints according to syndrome differentiation, and needling and galvanism were combined on the acupoints. Main acupoints were ST36, CV3 and CV4. Additional points for Shi were BL32 and LR3) and for Xu were LI4 and SP6.  Radio frequency electrodes (self‐developed, putting auricular needle in the centre of electrode plate with thumb‐tack needle) were inserted and connected to Han's acupoint nerve stimulator. Dilatational wave of 2Hz/100 Hz operated as a stimulator and the strength adjusted to the woman's tolerance level. 2) TENS group used Han's acupoint nerve stimulator and stimulated point with 2/100 Hz of dilatational wave.  3) Spinal‐epidural analgesia group received combined spinal and epidural block anaesthesia. 4) Advice on breathing during contraction and local massage during severe pain.
Outcomes	VAS scores of pain applied at pre‐pain, 30 minutes, 60 minutes, 120 minutes after pain analgesia, at the end of active stage (cervical dilation of 7 cm to 8 cm), complete dilation of cervix, second stage of labour, third stage of labour and 1 day after labour.  0‐no pain, 1‐mild pain, 10‐most severe and intolerable pain. Degree of satisfaction to labour analgesia 2 hours after delivery. Satisfied: pain completely relieved without evident discomfort. Relatively satisfied: pain relieved to some extent without evident discomfort. Unsatisfied: pain not relieved with evident discomfort. Mode of birth, maternal and labour complications.
Notes	Trial duration: April 2004 to February 2005. Funding: National Traditional Chinese Medicine Administration of Traditional Chinese Medicine Science and Techology Research Special TCM Clinical Research Fund (04‐05LQ04). Conflict of interest: not stated. Setting: delivery unit at the Beijing Gynaecology and Obstetrics Hospital. Country: China. Data from electro‐acupuncture and groups 3 and 4 were combined.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer generated.
Allocation concealment (selection bias)	Unclear risk	No details 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	Unclear risk	Not described.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No participant loss.
Selective reporting (reporting bias)	Unclear risk	Study protocol unavailable.
Other bias	Unclear risk	Insufficient reporting.