Wiener 1977a.

Methods	Randomised controlled trial
Participants	28 newborn infants, of gestation 38 to 42 weeks, whose mothers had been given pethidine in labour
Interventions	1. Naloxone administered via the umbilical vein at 1 minute of age (0.04 mg total): n = 10 2. Normal saline placebo: n = 18
Outcomes	Alveolar carbon dioxide tension, carbon dioxide excretion, alveolar ventilation, feeding behaviour, and habituation to a sound‐specific stimulus up to 48 hours of life
Notes	NICU, Wales, mid 1970s
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random allocation in pharmacy
Allocation concealment (selection bias)	Low risk	Coded ampoules
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Naloxone or normal saline were "chosen blind at random"
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Likely to have been blinded but not stated explicitly either way in the paper
Incomplete outcome data (attrition bias) All outcomes	Low risk	Complete follow‐up
Selective reporting (reporting bias)	Unclear risk	No protocol (though no reason to suspect selective reporting)
Other bias	Unclear risk	The study was stopped early because the randomisation code was broken after 28 infants had been enrolled.