Prenatal cocaine and neuromotor outcome at four months: effect of duration of exposure.

The effect of prenatal cocaine exposure on the motor development of full-term infants was examined in a prospective study, controlling for maternal characteristics and exposure to other substances. Intrauterine cocaine exposure was determined at birth by maternal self-report and was verified by hair analysis. At 4 months, 120 cocaine-exposed (COC) and 186 non-cocaine-exposed (NON-COC) infants were assessed by blinded examiners using a standard evaluation of neuromotor function, the Movement Assessment of Infants (MAI). Relative to NON-COC infants, COC infants had significantly higher full-scale MAI total risk scores after adjusting for covariates (p = .05). Infants exposed through the third trimester of pregnancy (n = 48) had higher MAI scores for both total risk (p = .02) and Volitional Movement (p = .01), and when compared with infants exposed only within the first two trimesters (n = 72), they had significantly more deficits in Volitional Movement (p = .03). Although MAI scores for the majority of exposed infants were within the normal range, infants exposed through the third trimester were at significantly increased risk for motor dysfunction (relative risk = 1.6; 95% confidence interval = 1.1, 2.8). Intrauterine cocaine exposure had an adverse effect on infant motor development after the neonatal period; this association was related to the timing and duration of gestational exposure. Further study is needed to evaluate the long-term clinical implications of neuromotor abnormalities in prenatally exposed infants.