The review addressed a well-defined question in terms of participants, interventions, study design and relevant outcomes. Relevant sources were searched and unpublished studies considered. However, language restrictions were applied, so some relevant studies may have been missed. Publication bias was not assessed. Only one reviewer undertook study selection and another reviewer data extraction, so error and bias could not be ruled out.
Trial quality was not formally assessed, so it was not possible to assess trial quality from the limited relevant data reported. The authors did not provide any information about how statistical heterogeneity was assessed. It was not clear whether the statistical analysis performed was appropriate and uncertainties regarding the setting of non-inferiority boundaries were acknowledged by the authors.
Given the small number of included trials of uncertain quality, and uncertainties about the review process, the authors’ results should be treated with caution.
Both authors disclosed financial links with Exelgyn SA (manufacturers of mifepristone).