This report is comprised of three separate studies conducted at the University of Colorado Medical Center. In the first study, answers to the following questions were sought: (1) What kinds of late morbidity occur at different birth weights and gestational ages? and (2) Has a vigorous approach to metabolic support in the newborn period changed the outcome of the low-birth-weight infants? In the second study, complications resulting from the use of indwelling unbilical vein catheters in newborn infants was studied when the infants were from 9 months to 2 years of age. In the third study, head shape and size of normal newborn infants were studied in their relationship to gestational age and birth weight. Results of the studies are discussed and tabulated. (Seven figures in the original document are not included because of nonreproducibility.) (DB)