Safarzadeh 2012.

Methods	RCT
Participants	150 primiparous women with a single foetus, who arrived at the labour ward in active labour (4 cm cervical dilatation). The age range of the women was 18 to 34 years, and gestational age was 38 to 42 weeks. None of the women had evidence of any severe obstetric disease
Interventions	This study was carried out in maternity wards of Zahedan and Mirjaveh, Iran from July 2007 to May 2008. Women in the intervention group received doula support during active labour from an untrained woman such as a female friend or relative (mother‐in‐law, mother, sister‐in‐law, sister) who had been selected by the mother. Women in the control group (without doula support) received routine care. To avoid contamination between the intervention and control groups, separate labour rooms, screens between the beds or beds at opposite ends of the same room were used
Outcomes	Severity of pain: using a VAS at the beginning of active labour (4 cm cervical dilation) and at the end of the second active phase of labour (10 cm cervical dilatation). Duration of the active phases of labour Mode of delivery Use of medication (oxytocin/promethazine/hyosin)
Notes	Unknown if companions were typically permitted on the labour ward, if continuous EFM was used routinely, or if epidural anaesthesia was available Dates of study: July 2007 to May 2008 Funding: not clear. Conflicts of interest: not reported.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	There is no mention of how the sequence was generated, e.g. “Subjects were selected using simple random sampling and were randomly divided into two groups: one group with doula support (n=75) and one control group (n=75)."
Allocation concealment (selection bias)	Unclear risk	There is no mention of how allocation was concealed, e.g. “Subjects were selected using simple random sampling and were randomly divided into two groups: one group with doula support (n=75) and one control group (n=75)."
Blinding of participants and personnel (performance bias) All outcomes	High risk	There is no mention of how participants and/or personnel were blinded, but blinding of participants and personnel is not possible
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	There is no mention of blinding of outcome assessment, e.g. "The severity of pain was measured in both groups using a Visual Analogue Scale at the beginning of active labour (4 cm cervical dilation) and at the end of the second active phase of labour (10 cm cervical dilatation). Duration of the active phases of labour, the type of delivery and the use of medication (oxytocin/promethazine/hyosin) in both groups were recorded."
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	The study states that 75 women were randomised to control and 75 randomised to intervention. However, neither the results section nor table 2 (relevant outcome data), report the total number of women for each outcome assessed
Selective reporting (reporting bias)	Low risk	Outcomes reported in the method section are reported in the results section
Other bias	Low risk	No evidence of other bias