In Canada, the leading cause of long-term disability in children is being born at very low birth weight (VLBW). To help improve outcomes, nutrition is a modifiable aspect of infant care. Mother's milk is the optimal way to feed VLBW infants; however, many need a supplement of donor milk or preterm formula as not enough mother's milk is available. As the ideal supplement for prolonged feeding and its long-term effects is currently unknown, this study is a prospective follow up of VLBW infants who in hospital were fed: donor milk or preterm formula and/or mother's milk. Areas of development to be assessed include: cognition, language, motor skills, brain structure/function, and body composition. A DNA biorepository will also be created.