The proposed study (ECCHO-NFGS) provides an unprecedented opportunity to understand mechanisms of in utero exposures on risk of childhood outcomes of public health significance. The data are of the highest quality, are the most detailed serial assessments of fetal development available in any cohort. We will demonstrate our ability to engage children and standardize our research protocols to address our hypotheses (UG3) and follow this cohort prospectively for future risk assessment (UH3). The NFGS is the ideal cohort to assess the prenatal determinants of two key health outcomes ? obesity and neuroimpairment as well as be a resource for the ECHO Consortium for all four outcome focus areas.