Head growth in cocaine-exposed infants: relationship to neonate hair level.

Intrauterine brain growth retardation is the most common brain abnormality in infants of cocaine-abusing mothers. We report a cross-sectional study of "at-risk" pregnancies with 34 infants born to mothers urine positive for cocaine at delivery compared to 33 infants born to urine-negative mothers from the same clinic. Degree of cocaine exposure was assessed by radioimmunoassay of combined cocaine and benzoylecgonine (BE) levels in neonatal hair samples. Twenty-eight neonates were hair-positive for BE (mean 2507.40 +/- 1248.88 ng/g hair; range 716 to 5440 ng/g) and differed significantly from the control infants (n = 33) in head circumference and head growth percentiles. A negative correlation approaching significance was found between mean BE and head circumference (r = -.36; p < .06) in the group of newborns with hair positive for BE (n = 28). The study demonstrates for the first time head growth abnormalities in association with levels of cocaine exposure.