Prenatal Exposure to Drug Abuse

The consequences of drug abuse during pregnancy do not stop at birth. A growing body ofevidence shows that prenatal exposure to alcohol, cocaine, tobacco, and other drugs of abuse can havelifelong consequences.

"There is no safe period for prenatal exposure to drugs of abuse," said Barry Kosofsky, MD,Division of Child Neurology, Weill Cornell Medical College, NewYork-Presbyterian Hospital. "Theexcess dopamine that is associated with abuse of these drugs can retard brain cell development, withconsequences that last into adulthood."

Fetal alcohol syndrome, for example, produces microcephaly in nearly all neonates, anddevelopmental delays in 90% of children. Typical problems include impaired intelligence, learning andmemory defects, shortened attention span, lack of remorse, little or no judgment, an inability tolearn from experience, and social aggression.

"FAS is not just the cognitive deficit, it is socialization, the inability to learn fromexperience," he explained. "These kids can't put together cause and effect in social interactions,and that creates lifelong problems."

Prenatal cocaine has a less profound impact on IQ than alcohol abuse, Dr. Kosofsky continued.But there are similar problems with altered behavior, alertness, orientation, delayed languageacquisition, poor impulse control, and poor attention span.

Maternal tobacco use is also associated with growth retardation, language development delays,hyperactivity, greater impulsiveness, and increased defiant behavior.

There is also emerging evidence in animal models that fetal exposure to drugs of abuseincreases the risk for abuse and addiction in later life. The animal studies support limited clinicaltrials that show a higher level of drug use by the offspring of mothers who used drugs duringpregnancy, he added.

A small head has emerged as the most reliable indicator or prenatal drug exposure, Dr.Kosofsky said. Any neonate whose head is smaller than two standard deviations from normal should bechecked for other physiological signs such as hypotonia (FAS) or hypertonic tetraparesis(cocaine).

"We think weight and length and blood pressure with neonates; we've got to measure headcircumference, too," Dr. Kosofsky said. "There aren't many other conditions that create symmetricalgrowth retardation that you can see at birth."