Fox 1993.

Methods	Single‐centre RCT.
Participants	101 women, 90 consented. Inclusion criteria: in documented preterm labour eligible; gestational age range: between 34‐37 weeks. Exclusion criteria: women with cervical dilatation ≥ 3 cm, ruptured membranes, medical or obstetric complications necessitating delivery, suspected anomalies, maternal allergy to magnesium sulphate. Total recruited: 101 women, 45 to magnesium (vs) 45 to control group (conservative management). Setting: Jackson, Mississippi, USA (timeframe not stated).
Interventions	MAGNESIUM VS CONSERVATIVE MANAGEMENT 1) Magnesium sulphate (n = 45): loading dose 4 g IV as a bolus. Maintenance: 2‐4 g/hr until uterine quiescence obtained. Duration: after uterine quiescence oral magnesium until 37 weeks' gestation. 2) Control group (n = 45): 'conservative management with hydration, sedation and observation'. 'Underwent an identical evaluation' however labour was allowed to continue.
Outcomes	Interval from diagnosis to delivery; gestational age at time of delivery; adverse effects of therapy; maternal infections; birthweight; neonatal morbidity and mortality. Serious infant outcome: able to be defined as perinatal mortality and IVH 3/4 and/or PVL.
Notes	Antenatal corticosteroid use: "not used in any patient". Surfactant use: not stated. Sample size calculation: stated but not a priori. Funding: Vicksburg Hospital Medical Foundation.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"table of random numbers".
Allocation concealment (selection bias)	Low risk	"randomisation was performed by using the sealed‐envelope method in which the group selection was generated from a table of random numbers. A disinterested third party (the pharmacy) was in charge of selection of the envelope for each patient. The treating physicians did not have access to the envelopes".
Blinding of participants and personnel (performance bias) All outcomes	High risk	Women were not blinded as interventions were IV drug vs usual management. Researchers would not be blinded to interventions.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No details but unlikely.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No evidence of loss after randomisation and ITT analysis conducted.
Selective reporting (reporting bias)	Low risk	Outcomes appear to be appropriate and all were reported on.
Other bias	Low risk	No apparent evidence of other bias.