Nutritional interventions during pregnancy for the prevention or treatment of impaired fetal growth: an overview of randomized controlled trials.

This paper reviews the efficacy of nutrition interventions to prevent or treat impaired fetal growth. Searches were made for Cochrane systematic reviews and randomized controlled trials published before October 2002. Balanced protein energy supplementation reduced the risk of small for gestational age (SGA) by 30% (95%CI: 20% to 43%) while one trial conducted in New York, U.S., reported a negative effect of high protein supplementation on SGA (RR 1.58; 95%CI: 1.03-2.41). Calcium supplementation protected against low birth weight (RR 0.83; 95%CI: 0.71-0.98). Micronutrient supplements did not affect birth weight, except for magnesium supplementation, which reduced the risk of SGA by 30%. This finding, however, needs or be interpreted with caution because of methodological issues in the data analysis. Programmatic recommendations can be made only for intervening with balanced protein energy supplements, especially in population with a high prevalence of undernutrition. Research is needed to determine the efficacy of multiple micronutrient supplementation and the effect of single micronutrients supplementation on specific growth outcomes such as fetal organ and bone growth. In addition, the public health relevance of these outcomes and their relation to morbidity need to be evaluated.