Su 2001.

Methods	4‐arm randomised controlled trial.
Participants	Women were full term (38‐42 weeks' gestation), primigravida, with singleton pregnancy, no cervical or obstetric diseases, healthy fetus, no cephalopelvic disproportion, no contraindications to vaginal delivery, no contraindications to spinal analgesia.
Interventions	1. HANS group (group I): acupuncture at ZhiYang point and JiZhong point. Stimulated at 2/100Hz at 6‐second intervals. The stimulation is at 2Hz and 100 Hz for 0.6ms and 0.2ms, respectively. All titrated up to patient tolerance; usually at 8‐12 mA for ZhiYang, and 15‐25mA for JiZhong point. The acupuncture is done hourly for a total of 30 minutes. 2. Placebo + PCEA (group II): intradural inserted at L3‐5 with lidocaine 6 mL; PCA is given at 4 mL per press, and is subsequently locked for 15 minutes; max is 20 mL per hour. Baseline is given at 0.1 mL per hour. 3. HANS + PCEA (group III): acupuncture as per group I and PCEA as per group II. 4. Control; no intervention (group IV): no intervention.
Outcomes	Maternal parameters (blood pressure in kPa, heart rate in beats per minute, breathing in breaths per minute): every 30 minutes from start of stage I labour to completion of delivery. SpO2 – oximetry every half‐hourly; if lower than 90%, given oxygen. Uterine contractions and time of labour. Fetal heart rate every 15‐30 minutes measurement. VAS pain scoring of 0 to 10, measured at pre‐intervention, and every half‐hour post intervention. Neonatal Apgar (1 minute, 5 minute). Adverse events: blood pressure decrease, respiratory arrest, nausea, urinary retention, those requiring labour augmentation (Intravenous or surgical caesarean delivery). Volume of PCEA used and number of PCA presses. Postpartum haemorrhage (total during delivery and up to 2 hours after).
Notes	Translated from Chinese.