Neuromotor development of cocaine-exposed and control infants from birth through 15 months: poor and poorer performance.

OBJECTIVE

The objective of this study is to describe the longitudinal course of motor development of a group of infants exposed to cocaine in utero and an unexposed control group.

METHODS

Subjects included 28 in utero-exposed infants and 22 unexposed infants matched for race, income of the family, and mother's educational level. Infants were evaluated at 1 month with the Alberta Infant Motor Scale (AIMS), at 4 months with the AIMS and Movement Assessment of Infants (MAI), at 7 months with the AIMS and MAI, and at 15 months with the Peabody Developmental Motor Scales (PDMS).

RESULTS

At 4 months, compared with the unexposed infants, a significantly larger proportion of the exposed infants fell below the 50th percentile on the AIMS and had greater proportion of suspicious risk scores on the MAI. At 7 months infants in the exposed group had lower AIMS and MAI scores than the control group. There was no difference between groups on the motor scales at 1, 4, or 15 months. At all ages more infants in both groups scored significantly less than the expected norms on all scales. Performance was unrelated to a cumulative risk index made up of demographic, medical, and social factors. Almost all subjects had risk scores that placed them at extremely high levels of risk. Performance may have been related to a difference in weight between groups at 7 months and to decreasing weights for both groups by 15 months.

CONCLUSION

In utero cocaine exposure has a significant, although relatively small, effect on infant motor performance late in infancy. However, regardless of exposure status, these infants had poor performance that may be accounted for by a heavy accumulation of risk factors associated with poverty.