IntroductionMaternal health and the performance of health workers is a key concern in low- and middle-income countries. Mobile health technologies are reportedly able to improve workers? performance. However, how this has been achieved for maternal health workers in low-resource settings is not fully substantiated. To address this gap by building theoretical explanations, two questions were posed: How does mobile health influence the performance of maternal health care workers in low- and middle-income countries? What mechanisms and contextual factors are associated with mobile health use for maternal health service delivery in low- and middle-income countries?MethodsGuided by established guidelines, a realist review was conducted. Five databases were searched for relevant English language articles published between 2009 and 2016. A three-stage framework was developed and populated with explanatory configurations of Intervention?Context?Actors?Mechanism?Outcome. Articles were analyzed retroductively, with identified factors grouped into meaningful clusters.ResultsOf 1254 records identified, 23 articles representing 16 studies were retained. Four main mechanisms were identified: usability and empowerment explaining mobile health adoption, third-party recognition explaining mobile health utilization, and empowerment of health workers explaining improved competence. Evidence was skewed toward the adoption and utilization stage of the framework, with weak explanations for performance outcomes.ConclusionsFindings suggest that health workers can be empowered to adopt and utilize mobile health in contexts where it is aligned to their needs, workload, training, and skills. In turn, mobile health can empower health workers with skills and confidence when it is perceived as useful and easy to use, in contexts that foster recognition from clients, peers, or supervisors.