Effects of iron supplementation in nonanemic pregnant women, infants, and young children on the mental performance and psychomotor development of children: a systematic review of randomized controlled trials.

BACKGROUND Uncertainty exists regarding the effects of iron supplementation on neurodevelopmental outcomes in the absence of anemia. OBJECTIVE Our objective was to evaluate the effects of iron supplementation in nonanemic pregnant women and in nonanemic healthy children aged <3 y on the mental performance and psychomotor development of children. DESIGN In this systematic review, MEDLINE, EMBASE, and The Cochrane Library were searched through December 2009 for randomized controlled trials (RCTs). RESULTS None of 5 RCTs individually showed a beneficial effect of iron supplementation during early life on the Mental Developmental Index of the Bayley Scales of Infant Development at different ages throughout the first 18 mo. Meta-analysis of 3 RCTs (n = 561) showed that, compared with placebo, supplementation with iron had no significant effect on children's Mental Developmental Index at approximately 12 mo of age (weighted mean difference: 1.66; 95% CI: -0.14, 3.47). Three of 5 RCTs showed a beneficial effect of iron supplementation on the Psychomotor Development Index at some time points, whereas 2 did not. Meta-analysis of 3 RCTs (n = 561) showed significant improvement on the Psychomotor Development Index at approximately 12 mo of age in the iron-supplemented group compared with the control group (weighted mean difference: 4.21; 95% CI: 2.31, 6.12). Two RCTs showed no effect of iron supplementation on behavior. Neither of the 2 RCTs that addressed the influence of prenatal iron supplementation showed an effect of iron on either the intelligence quotient or behavioral status of the children. CONCLUSION Limited available evidence suggests that iron supplementation in infants may positively influence children's psychomotor development, whereas it does not seem to alter their mental development or behavior.