Lewycka 2013b.

Methods	2 by 2 factorial cluster RCT conducted in Malawi between 2005 and 2009. Lewycka 2013b describes the same trial as Lewycka 2013a above, and all of the descriptions and risk of bias are identical to that above. We have had to duplicate the 'Risk of bias' judgements below due to RevMan requirements.
Participants	For the analysis in our review's Comparison 1: Lewycka 2013a refers to the women's group intervention only. Lewycka 2013b refers to the peer counselling intervention only. These 2 single‐intervention arms are compared to the arm with no intervention.
Interventions	See Lewycka 2013a.
Outcomes	See Lewycka 2013a.
Notes	See Lewycka 2013a.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation done with computer program Stata.
Allocation concealment (selection bias)	Unclear risk	Not described.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not blinded.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Group assignment was masked for data analysis. Data collection was conducted independently of program implementation and was not fed back to inform the intervention.
Recruitment bias (for cluster RCTs)	Low risk	None noted.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Women with miscarriages were excluded from analysis. Loss to follow‐up about 20%. Miscarriage rates varied across study arms and were more frequent in the combined intervention cluster.
Selective reporting (reporting bias)	Low risk	Relevant outcomes reported.
Analysis bias	Low risk	Analysis appropriate for clusters; no ICC reported; ITT analysis performed.
Other bias	Unclear risk	The authors discuss an interaction between the 2 interventions and baseline imbalances after randomisation across several outcomes.
Overall risk assessment	Unclear risk	We were concerned that the exclusion of women with miscarriages might bias maternal death rates.