<b><i>Background/Aims:</i></b> Iron deficiency (ID) and iron deficiency anemia (IDA) are global health concerns associated with adverse perinatal effects. Despite efforts taken at the international level, there is no consensus on unified prevention/treatment strategies, largely stemming from inconsistencies of outcome reporting. Our objective was to comprehensively assess outcome reporting perinatal iron intervention trials as Phase 1 of core outcome set (COS) development to inform future research. <b><i>Methods:</i></b> Systematic search in MEDLINE, EMBASE, Cochrane Databases, and CINAHL (January 2000 – April 2016), with inclusion of trials involving pregnant or postpartum women with ID/IDA confirmed before recruitment. Articles were independently screened and selected by 2 reviewers; data were extracted in duplicate. Quality was assessed using published scoring systems. Outcome definitions and measurement methods were tabulated. <b><i>Results:</i></b> Of 7,046 citations, 33 randomized controlled trials were included. Sixty-nine reported outcomes were categorized into 8 domains. High methodological quality characterized 25 (76%) studies. Reporting quality was low in 16 (49%), moderate in 13 (39%), and high in 4 (12%) studies. Variation was greatest for outcome definition, timing of assessment and measurement methods. <b><i>Conclusion:</i></b> This review identifies a comprehensive long-list of outcomes reported of perinatal iron interventions for ID/IDA. Beyond highlighting existing variation in outcome reporting, it provides a foundation for development of a COS for future trials.