PRENATAL COCAINE AND NEONATAL OUTCOME - EVALUATION OF DOSE-RESPONSE RELATIONSHIP

Objective. The aim of this study was to evaluate the hypothesis that p renatal cocaine exposure would negatively affect newborn behavior. Met hods. A prospective observational study of term infants recruited from the low-risk nursery used a structured, standardized interview to obt ain maternal data. Cocaine exposure was determined by radioimmunoassay of the infants meconium stool. An examiner blinded to the infant's co caine status administered the Brazelton Neonatal Behavioral Assessment Scales. Results. The sample was composed of 23 exposed and 29 nonexpo sed infants. On six of the seven Brazelton Neonatal Behavioral Assessm ent Scale clusters, cocaine-exposed infants performed less well than c ontrol infants, with significant differences observed for autonomic st ability. In addition, a dose-response relationship was suggested. Sign ificant negative, within-group relationships were evident in the expos ed group, indicating poorer performance with increasing meconium cocai ne concentration for orientation (r = -.40) and regulation of state (r = -.40). Regression model testing of the influence of meconium cocain e concentration on neurobehavioral outcomes, after controlling for sig nificant confounders, identified a significant independent, negative e ffect of meconium cocaine concentration on two clusters--motor and reg ulation of state. Conclusion. In otherwise healthy full-term infants, prenatal cocaine exposure identified by quantitative analysis of cocai ne concentration in meconium had a significant, independent negative a ssociation with motor and regulation of state that remained after cont rolling for other significant confounders. A dose-response relationshi p was evident.