Edward 2013.

Methods	Design: RCT Unit of randomisation: mothers Intention to treat: yes Adjustment for clustering: N/A. Parallel‐group study
Participants	Total number randomised: 248 pregnant women (intervention‐ doula group: 124; control: 124) Inclusion criteria: women who were < 34 weeks pregnant, under 21 years of age, and planning to deliver at the affiliated hospital Exclusion criteria: mothers who were aware at the time of recruitment that they would require a surgical delivery, who planned to move from the area, or who planned to give up custody of the infant Age: newborn infants enrolled and followed up to age 4 months Gender: not reported Ethnicity: young, African‐American mothers Setting: a major urban university hospital and community Country: unclear Attrition: intervention: 16/124 (12.9%); control: 11/124 (8.9%)
Interventions	Intervention (see Table 4 for detailed description): breastfeeding advocacy timing of introduction of complementary foods Control: treatment as usual Duration of each intervention session: not reported
Outcomes	Attempted breastfeeding at the hospital Breastfeeding duration Timing of introduction of complementary foods Time points reported: 4 months
Notes	Study start and end dates: unclear Study duration: unclear Conflict of interest: the study authors indicated they had no potential conflicts of interest to disclose Source of funding: "all phases of the research study reported in this paper were supported by the Maternal and Child Health Bureau Research Program, HRSA, DHHS, grant R40 MC 00203. The intervention implementation was funded by grants from the Irving B. Harris Foundation, the Blowitz‐Ridgeway Foundation, the Prince Charitable Trusts, the Visiting Nurses Association Foundation, and the Michael Reese Health Trust." (quote, p s160)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "randomisation took place in blocks of 4, 6, or 8, with equal numbers assigned to the intervention and control groups within each block" (p s162)
Allocation concealment (selection bias)	Low risk	Quote: "a biostatistician prepared a set of opaque envelopes, each labelled with a subject ID number and containing a group assignment" (p s162)
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Comment: not described. Probably not done
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Comment: not described. Probably not done
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: overall attrition was low about 11%. All participants lost to follow‐up were accounted with reasons. 12.9% from intervention and 8.9% from control group Quote: "all analyses were by intent‐to‐treat" (p s163)
Selective reporting (reporting bias)	Unclear risk	Comment: none observed, but no protocol available for assessment
Other bias	Low risk	Comment: none observed