The plasma concentrations of noradrenaline, DHPG, and DOPAC were measured by HPLC with coulometric electrochemical detection24 with interassay CVs of 5.9%, 3.3%, and 1.8% at mean concentrations of 1.4, 5.2, and 15.2 nmol/L, respectively (to convert noradrenaline, DHPG, DOPAC to micrograms per liter, multiply by 0.17). The corresponding quantitation limits were 0.05, 0.5, and 1.0 nmol/L. The concentrations of serotonin, 5-HIAA, and HVA were measured by HPLC with electrochemical detection.25 The interassay CVs were 5.5%, 5.5%, and 4.3% for serotonin, 5-HIAA, and HVA at mean concentrations of 440, 43.5, and 91.3 nmol/L, respectively (to convert serotonin, 5-HIAA, and HVA to micrograms per liter, multiply by 0.18, 0.19, and 0.18, respectively). The limits of quantitation were 3.0 nmol/L for serotonin and 5-HIAA and 6.0 nmol/L for HVA. The cord blood serum prolactin was assayed by a noncompetitive immunoradiometric assay kit (Spectria Prolactin IRMA; Orion Diagnostica, Espoo, Finland) with an interassay CV of 3.1% at 3789 mU/L and lower limit of quantification of 50 mU/L.