Strengths and limitations

Our findings are strengthened by the comprehensive search strategy. We used the same tried and tested search strategy employed in several previous reviews relevant to maternal and newborn health.2,5,13-16 Building on past reviews we further included COS specific to clinical practice. We believe this is the first application of the COS-STAD criteria to evaluate the COS development process relevant to maternal and neonatal health, making the findings pertinent to the CROWN Initiative. For consistency, we applied identical COS-STAD assessment criteria to that of Gargon et a., in their assessment of cancer-related COS;9 the first report using COS-STAD criteria. Despite our efforts, our findings do have some limitations. Due to resource limitations, the search and screening process was conducted primarily by one person (VS). Although ten percent of papers were evaluated by a second person (DC), it is possible that some COS papers may have been missed. Assessing each standard against COS-STAD criteria was challenging. Some assumptions were made, particularly in terms of stakeholder involvement. For example, we assumed those who would use the COS in research were involved when participants were conference delegates or expert working groups. It is possible that this may have not been the case. In contrast to Duffy et al.,6 we have not reported COS in development. A quick search of the COMET database identified 44 COS in development related to maternal and neonatal health. Future COS developers and users are encouraged to review the COMET database of ongoing and completed COS.