Aramayo 1990.

Methods	Single‐centre RCT.
Participants	30 women. Inclusion criteria: in preterm labour between 28‐36 weeks' gestation with intact membranes. The diagnosis of labour was made if persistent uterine contractions occurred 3 times in 10 minutes and cervical examination suggested 'active labour'. Gestational age range: 28‐36 weeks. Exclusion criteria: cervical incompetence, congenital malformation, ruptured membranes, fetal death, maternal cardiac disease. Setting: Mexico, 1988‐1989.
Interventions	MAGNESIUM VS BETAMIMETICS 1) magnesium sulphate (n = 15): loading dose 4 g IV; maintenance 2 g/hr; 2) terbutaline for labour inhibition (n = 15): 1.25 mg in 500 mL dextrose given at 10 drops per minute; followed by 5 mg oral tablet 8 hourly.
Outcomes	Postponement of birth for at least 48 hrs after initiation of therapy; 2‐6 days, 7‐12 days, > 12 days after treatment; preterm birth.
Notes	Antenatal corticosteroid use: not stated. Surfactant use: not stated. Sample size calculation: not stated. Funding: not stated.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"randomised study."
Allocation concealment (selection bias)	Unclear risk	"randomised study"; no further details reported.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not feasible to blind the interventions.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No mention of outcome assessors being blinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	1 woman in the terbutaline group was excluded because of severe fetal distress.
Selective reporting (reporting bias)	Unclear risk	Only infant outcome reported was preterm birth; no maternal health outcomes reported.
Other bias	Low risk	No apparent evidence of other bias.