PROTOCOL OUTLINE: This is a randomized, double blind study in arms I and II. Patients are randomized to receive either fortified pasteurized donor human milk (arm I) or preterm formula (arm II) as a supplement to mother's milk, if needed. Patients are stratified according to gestational age (less than 26 weeks vs 27-29 weeks) and prior antenatal steroids (yes vs no). Patients are also assigned to groups receiving fortified mother's milk (arm III) and preterm formula only (arm IV). Milk samples are obtained from the patient's mother for analyses of functional antibody against Staphylococcus epidermidis and Staphylococcus aureus; bacterial culture and sensitivity; bacterial colony count; and immunoglobulin and nutrient composition (i.e., energy, protein). Maternal blood samples to measure functional antibody are obtained every 2 weeks throughout hospitalization as long as infant is receiving own mother's milk. Cord blood is obtained at delivery. Patients are studied at 40 week postmenstrual age, and then every 6 months for 3 years. Records of health (e.g., number of doctor, clinic, and emergency room visits; hospitalizations; and illnesses), dietary intake, and growth are collected. Urine is collected every 2 weeks to monitor infection. Neurodevelopment is assessed at 3 years using the McCarthy Scales of Infant Development.

Mothers who plan to nurse their infants after hospital discharge complete the STAI "trait" form at beginning of study. Mothers are assessed weekly for 6 weeks postpartum, and every other week thereafter as long as they are expressing milk by mechanical means only. Following a session of skin to skin contact, the number of milk expressions, the duration of each pumping, and a 24 hour milk collection is obtained. Mothers also complete the Spielberger State Trait Anxiety Inventory, STAI, Beck Depression Inventory, Norbeck Social Support questionnaire, Parental Stressor Scale, and the Neonatal Perception Inventory during each 24 hour milk collection.