Reports of the effects of prenatal cocaine exposure on infant outcome have been inconsistent. This study evaluated the effects of maternal cocaine/opiate(C/O) use during pregnancy (as assessed by history and/or meconium assay) and of birthweight (≤ 1500 g, 1501-2500 g, > 2500 g) on infant mental, motor, and behavioral performance at one year (corrected for prematurity). As part of a multicenter (Brown U, U of Miami, U of Tennessee Memphis, & Wayne State U), longitudinal investigation, blinded examiners administered the Bayley Scales of Infant Development (BSID-II; Bayley, 1993) to 471 C/O exposed(EXP) infants and 559 non-exposed (NON) infants who had been matched by race, sex, and gestational age. On the BSID-II Mental Development Index (MDI), both C/O exposure (EXP=90.4±10.8, NON=92.2±11.3; p <.01) and birthweight (p <=.0001) had small but significant effects on performance (see below). Lower birthweight (but not C/O exposure) was also associated with lower scores on the Motor Development Index (p≤.0001), and on the total Behavior Rating Scale percentile (p<.005). For all measures, when effects of socioeconomic status(Hollingshead), testing center, and gender were controlled, the birthweight effect remained but the C/O exposure effect, where present, was eliminated. In sum, prenatal C/O exposure was not associated with clinically relevant deficits in mental or motor skills, or indices of behavioral difficulties during testing. The results highlight the importance of longitudinal evaluation of C/O exposed infants to identify factors which may influence their mental, physical, and behavioral development at later ages. Table

Table 1 Bayley II MDI
Full size table