Iron supplementation, mostly with a therapeutic orientation, has been a key strategy for the short-term control of iron deficiency and ferropenic anemia. It has been used almost exclusively in antenatal clinics, but in spite of its confirmed efficacy in supervised trials, it has proven ineffective in practice in most developing countries. Poor effectiveness has been attributed to various factors including insufficient dose and time of supplementation and poor adherence. These problems have led to the administration of high iron doses, which have proven equally ineffective in practice. This paper introduces four concepts: (1) that iron supplementation targeted to pregnant women should cover the full reproductive cycle, from prepregnancy to at least the end of lactation instead of only the pregnant woman; (2) that entering pregnancy with iron deficiency contributes to the failure of antenatal iron supplementation and that prepregnancy iron reserves increase the effectiveness of antenatal supplementation; (3) that medium- to long-term weekly ingestion of proper iron-folate supplements, with a preventive aim and directed to all risk groups, should be community based rather than health service based but supervised by the latter (in this sense, preventive supplementation is equal to targeted iron fortification); and (4) that preventive supplementation, based on weekly dosing, has proven efficacious. Problem-oriented research to evaluate the sustainability and medium- to long-term efficacy of these concepts is called for. The bases for the concepts and suggestions are summarized in this paper.