Neonatal addiction: a two-year study. Part I. Clinical and developmental characteristics of infants of mothers on methadone maintenance.

Thirty-five infants born over a two-year period to mothers participating in a methadone-maintenance treatment program were studied The average birthweight was normal (3240 gms) for infants born to mothers who conceived while taking methadone, and 465 gms less (2775 gms) for infants conceived while their mothers were taking heroin (p less than .01). Sixty percent of the infants demonstrated mild or no symptoms and 40% developed moderate or severe symptoms. The infants whose symptoms were most severe were born to mothers who had documented histories of polydrug abuse. Many infants were slow to gain weight in the neonatal period. Thereafter growth and development have remained generally within the normal range.