The development of motor asymmetries in 1-month-old infants who were prenatally exposed to cocaine.

The development of motor asymmetries was assessed in 20 infants who were prenatally exposed to cocaine and 23 comparison infants. Asymmetries in stepping, grasping, and head orientation were assessed at 1 month of age. As expected based on the findings of previous research with high-risk infants, infants who were prenatally exposed to cocaine performed a grasping task with their right hand for significantly shorter durations than comparison infants and were less likely to show a dominant hand preference than comparison infants. Comparison infants were also more likely to display a side bias for head orientation and stepping than infants who were prenatally exposed to cocaine. These findings suggest that prenatal exposure to cocaine may alter the typical developmental trajectory of functional asymmetries and may have important implications for long-term developmental outcomes.