The measurement of haloperidol and reduced haloperidol in neonatal hair as an index of placental transfer of maternal haloperidol

Hair samples were collected at time of delivery from three neonates and their schizophrenic mothers, who had been taking haloperidol (HP) during the perinatal period to control worsening psychotic symptoms. Maternal hair was cut into 1-cm lengths, and concentrations of HP and its major metabolite, reduced haloperidol (RHP), were measured by high-performance liquid chromatography. Neonatal hair was cut into halves, and the concentrations of HP and RHP in each half were measured. The distribution of both HP and RHP along the maternal hair paralleled the dosage of HP when hair growth was assumed to be 1 cm per month. In the upper half of hair from each of two neonates neither HP nor RHP was detected. Only HP was detected in the lower half from one, and a small peak of HP in the chromatogram was observed in the other, though under the detection limit. In the third neonate both HP and RHP were detected from both halves of hair, but the concentration of HP was larger in the lower half than in the upper. These findings suggest the possibility of monitoring the transfer of maternal HP through placenta by measuring HP and RHP concentrations in neonatal hair.