This is an overview of 126 randomized controlled trials (RCTs) evaluating 36 prenatal interventions to prevent or treat impaired fetal growth (IFG). Results are based on systematic reviews including the meta-analyses of these RCTs. Most of the prenatal interventions do not show any significant effects on short-term perinatal outcomes. There are, however, a few interventions likely to be beneficial: smoking cessation, antimalarial chemoprophylaxis in primigravidae, and balanced protein/energy supplementation. Others merit further research: zinc, folate, and magnesium supplementation during gestation. Appropriate combinations of interventions should be a priority for evaluation because it is unlikely that a single intervention will reduce a multicausal outcome like IFG that is so dependent on socioeconomic disparities. Of concern is the discrepancy between the importance given in the epidemiological and clinical literature to the problem of IFG and the methodological quality and sample size of the RCTs conducted for the evaluation of preventive or treatment modalities.