Nutritional interventions to prevent intrauterine growth retardation: evidence from randomized controlled trials.

This report summarizes the evidence from systematic reviews of randomized controlled trials on the effectiveness of nutritional interventions aimed at reducing intrauterine growth retardation (IUGR). There were 12 interventions including protein-energy, vitamin, mineral, and fish oil supplementation, as well as the prevention and treatment of anemia and hypertensive disorders. A primary concern is the limited data supporting the effectiveness of recommended nutritional interventions during pregnancy, some of which are widely used even in women without nutritional deficiencies. Overall, with the exception of perhaps balanced protein/energy supplementation (typical odds ratio: 0.77; 95 per cent confidence interval: 0.58 to 1.01), no effective nutritional interventions for reducing the risk of IUGR have been demonstrated. Other interventions, such as zinc, folate and magnesium supplementation during gestation, merit further research which should be conducted among populations at risk of IUGR, using larger sample sizes, and addressing coexisting factors limiting fetal growth. Appropriate combinations of interventions should be a priority for evaluation as it is unlikely that a single factor will reduce a multicausal outcome like IUGR that is so dependent on socioeconomic disparities.