Risk From Heavy Use
"The popular preception is that any prenatal exposure to cocaine is almost certainly associated with devastating effects on the neonate. However, these data suggest that most potentially detrimental effects (including neonatal size,38 neonatal behavior,12,13 and central nervous system lesions47) of prenatal cocaine exposure occur disproportionately among the heaviest users, a phenomenon also noted for alcohol and cigarette exposure.23"
Frank, Deboray A.; Augustyn, Marilyn; and Zuckerman, Barry S., "Neonatal Neurobehavioral and Neuroanatomic Correlates of Prenatal Cocaine Exposure: Problems of Dose and Confounding," Annals of the New York Academy of Sciences (New York, NY: New York Academy of Sciences, June 21, 1998), Vol. 846. p. 44.