<qa>  How many phases were conducted in the first three years of the study?This is a longitudinal, multi-site observational study of the long-term effects of a mothers use of cocaine andor opiates during pregnancy on her infant. This observational study evaluates the medical, developmental, social, environmental, and neurobehavioral outcomes for 1,400 of the original cohort of children. A series of follow-up examinations of these children were conducted in 5 phases: 1-36 months, 3.5-7 years, and 8-11 years. Children are currently being examined at 13 years of age. 