The main purpose of this study is to extend the investigators' previous research to longitudinally examine the effectiveness of three early intervention programs: usual care program, clinic-based intervention program and home-based intervention program for very low birth weight preterm children at 3 and 4 years of age. Normal weight full-term children will also be included to serve as the reference group. Effectiveness assessments will include child, parenting, and transactions measures. Child outcome measures will include health status, growth, neurodevelopment and behavior; parenting outcome measures will include parental stress, competence, efficacy and family support; transactions outcome measure will include parent-child interaction procedures.