Kovacs 1990.

Methods	RCT. Women recruited from 4 private obstetric practices, May 1985–June 1987, Australia.
Participants	50 pregnant women aged 20‐40, more than 20 weeks pregnant and having experienced moderately severe heartburn at least once a day in the previous week. Women with known gastrointestinal disorders, systemic medication or chronic respiratory diseases, emphysema or recurrent pneumonia were excluded. Women had moderate and severe degree of heartburn at study entry.
Interventions	Intervention groups: mucaine with oxethazaine, mucaine. Data for these women have been combined for analysis. N = 32. Comparison group: placebo. N = 18. Study duration: 1 week. Intervention and treatment were provided in identical bottles. Women were allowed to take an antacid if treatment was not successful after 15 minutes of the drug dose. Women were asked to record the severity of heartburn before the trial and after the 7 day study period, as well as the number of doses used each day and antacids taken. Side effects were also recorded at the end of the week.
Outcomes	Relief of heartburn, symptoms severity and relief, use of medication, willingness to use the medication again. All outcomes were analysed using mean and standard deviation
Notes	This study was supported by Wyeth Pharmaceuticals. Heartburn relief data were not used in the analysis as it were presented as a mean.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Sequence generation not described. Study described as randomised.
Allocation concealment (selection bias)	Low risk	Women allocated to trial number in sequence. Identical treatments and placebo prepared, so that staff and women would not have been aware of the next allocation.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Treatment and placebo identical.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Treatment and placebo identical.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Data for all women recruited.
Selective reporting (reporting bias)	Low risk	All relevant outcomes appear to have been reported.
Other bias	Unclear risk	This study was supported by Wyeth Pharmaceuticals.