Reisfield 1971.

Methods	RCT. Not clear how randomisation was carried out.
Participants	156 pregnant women attending hospital clinic complaining of heartburn.
Interventions	Intervention group ‐ magnesium and aluminium hydroxide and simethicone (tablets and liquid preparation) (MYLANTA). Comparison group ‐ placebo tablet and liquid preparations of an identical appearance.
Outcomes	Heartburn relief.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No information provided, described as pre‐determined random basis.
Allocation concealment (selection bias)	Low risk	Not stated.
Blinding (performance bias and detection bias) Women	Low risk	Placebo controlled study.
Blinding (performance bias and detection bias) Clinical staff	Low risk	Placebo controlled study.
Blinding (performance bias and detection bias) Outcome assessors	Unclear risk	Not stated.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Data available for most participants.

RCT: randomised controlled trial