Research Review: Maternal prenatal distress and poor nutrition - Mutually influencing risk factors affecting infant neurocognitive development

Background: Accumulating data from animal and human studies indicate that the prenatal environment plays a significant role in shaping children's neurocognitive development. Clinical, epidemiologic, and basic science research suggests that two experiences relatively common in pregnancy - an unhealthy maternal diet and psychosocial distress - significantly affect children's future neurodevelopment. These prenatal experiences exert their influence in the context of one another and yet, almost uniformly, are studied independently. Scope and Method of Review: In this review, we suggest that studying neurocognitive development in children in relation to both prenatal exposures is ecologically most relevant, and methodologically most sound. To support this approach, we selectively review two research topics that demonstrate the need for dual exposure studies, including exemplar findings on (a) the associations between pregnant women's inadequate maternal intake of key nutrients - protein, fat, iron, zinc, and choline - as well as distress in relation to overlapping effects on children's neurocognitive development; and (b) cross-talk between the biology of stress and nutrition that can amplify each experience for the mother and fetus,. We also consider obstacles to this kind of study design, such as questions of statistical methods for 'disentangling' the exposure effects, and aim to provide some answers. Conclusion: Studies that specifically include both exposures in their design can begin to determine the relative and/or synergistic impact of these prenatal experiences on developmental trajectories - and thereby contribute most fully to the understanding of the early origins of health and disease.