PROJECT SUMMARY/ABSTRACT DESCRIPTION: See instructions. This must contain a summary of the proposed activity suitable for dissemination to the public (no proprietary/confidential information). It should be a self-contained description of the project and contain a statement of objectives and methods to be employed. It should be informative to other persons working in the same or related fields. DO NOT EXCEED THE SPACE PROVIDED. Although the health, social, and economic impacts of opioid addiction on adults and their communities are well known, the impact of maternal opioid use and misuse on the fetus exposed in utero is less well understood. The ACT NOW Outcomes of Babies with Opioid Exposure (OBOE) Study is a longitudinal cohort study to prospectively examine the medical, neuroanatomical, neurodevelopmental, behavioral, and social/family/home outcomes of children who were exposed to opioids in utero as compared with matched controls. The objectives of the ACT NOW OBOE Study are (1) to determine the impact of antenatal opioid exposure on brain structure and connectivity over the first 2 years of life; (2) define medical, developmental, and behavioral outcomes over the first 2 years of life in infants exposed to opioids; and (3) explore whether and how the home environment, maternal mental health, and parenting modify trajectories of brain connectivity and neurodevelopment over the first 2 years of life. We hypothesize that neural connectivity and neuroanatomical volumes are altered by prenatal opioid exposure and that the magnitude of these alterations correlate with developmental and behavioral outcomes. Further, maternal and environmental factors interact with prenatal opioid exposure to influence the trajectories of connectivity, development, and behavior over the first 2 years of life. The OBOE Study Consortium includes four Clinical Sites (Case Western Reserve University, Children's Hospital of Philadelphia, Cincinnati Children's Hospital Medical Center, and the University of Alabama at Birmingham) and an independent Data Coordinating Center at RTI International, composed of an Administrative Core and a Research Support Core. The consortium also includes a Neuroimaging Core at the Children's National Hospital, which has an extensive track record of studying brain development in healthy and high-risk fetuses, newborns, and infants using advanced, serial, multimodal magnetic resonance imaging methods. The goals of this administrative supplement to the ACT NOW OBOE Study are (1) to increase the sample size for the study, thereby improving the statistical power to detect differences in outcomes, particularly categorical and/or less common outcomes, between opioid-exposed and unexposed infants; and (2) to include additional measures of infant sleep and caregiver–infant interactions to allow for harmonization with other ACT NOW studies.