Neonatal intensive care has led to dramatic increases in the survival rates for very low birthweight infants. Despite this accomplishment, however, morbidity remains high and complications of therapy are frequent. New technologies, procedures, treatments and drugs are often introduced into neonatal intensive care without adequate scientific evidence of their safety and efficacy. The relatively small number of patients treated in any individual neonatal intensive care unit (NICU) has made it difficult to perform prospective studies with sufficient power to properly evaluate many of the rapidly emerging treatment strategies. The objective of this study is to facilitate evaluation of these strategies by establishing a cooperative network of neonatal intensive care centers that, by vigorous patient evaluation using common protocols, can study large numbers of patients and provide answers more rapidly than individual centers acting alone. The program staff of the National Institute of Child Health and Human Development will aid the investigators in cooperating NICUs to identify research topics of high priority and design appropriate experimental protocols to address these topics. The project will consist of four phases including 1. the identification and prioritization of important issues in clinical neonatology; 2. design of diagnostic and treatment protocols; 3. institution of protocols, data collection and transfer and 4. future planning. Short and long-term follow-up of patients will be crucial to the proposed studies since survival alone is not an adequate endpoint for evaluating the consequences of neonatal disease and the therapeutic interventions used in their treatment. The NICUs at the Medical Center Hospital of Vermont in Burlington, Vermont and the Dartmouth-Hitchcock Medical Center in Hanover, New Hampshire are level III centers providing a full range of neonatal services to inborn and transported infants from Vermont, New Hampshire and upstate New York. These centers have cooperated in regionalization of neonatal care, outreach education and clinical research since 1972 through the Vermont-New Hampshire Regional Perinatal Program. The directors and staffs of the two centers are firmly committed to the cooperative approach to clinical research in neonatology and have the patient population, resources, experience and dedication necessary to make the cooperative multicenter network of NICUs a success.