Methods	RCT. No information on how randomisation was carried out.
Participants	30 pregnant women with 4 or more moderate to severe episodes of heartburn per week
Interventions	Intervention group: calcium carbonate antacids and H2receptor antagonist (Ranitidine) Control group: calcium carbonate antacid and placebo.
Outcomes	Heartburn intensity.
Notes	Relatively large numbers of eligible women withdrew (already had relief with antacids alone) before randomisation
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No information provided.
Allocation concealment (selection bias)	Unclear risk	No information provided.
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 all women randomised.