Methods	RCT 2-arm parallel group design.
Participants	Setting: South Africa - hospital. 75 women. Healthy with no clinically detectable abnormality, in active labour, spontaneous and induced, and requiring analgesia. Excluded if history of hypersensitivity to any drug, previous caesarean, preterm labour, cardiac, pulmonary or renal disease and significant hypertension Parity: mixed.
Interventions	Experimental: IM meptazinol 100 mg (N = 37). Control: IM pethidine 100 mg (N = 38). No concomitant analgesia given, metoclopramide 10 mg as required for nausea
Outcomes	Maternal outcomes: pain at 1 hr 5-point VAS scale, drug-related side effects. Neonatal outcomes: Apgar at 1 and 5 min, paediatrician assessment at 24 hours
Notes
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not reported.
Allocation concealment (selection bias)	Unclear risk	Not reported.
Blinding (performance bias and detection bias) Women	Unclear risk	States double blind but does not describe how blinding achieved
Blinding (performance bias and detection bias) Clinical staff	Unclear risk	States double blind but does not describe how blinding achieved
Blinding (performance bias and detection bias) Outcome assessor	Unclear risk	States double blind but does not describe how blinding achieved
Incomplete outcome data (attrition bias) All outcomes	High risk	Number of women randomised not reported only number analysed, not same numbers analysed for all outcomes
Selective reporting (reporting bias)	Unclear risk	Unclear.
Other bias	Unclear risk	Women requiring caesarean or epidural were excluded from further study, unclear if this is pre- or post-randomisation