['This study compares plasma lidocaine concentrations in 16-sets of twin neonates to 16-singleton neonates all of whom were delivered by Cesarean section under lumbar epidural anesthesia (LEA).', 'Lidocaine 1.5% with epinephrine 5 microg x mL(-1) was used for activation of LEA. Upon delivery plasma lidocaine concentrations were measured from the maternal vein (MV), neonatal umbilical vein (UV) and umbilical artery (UA) using TDx fluorescence polarization immunoassay.', 'MV lidocaine concentrations were similar in both twin and singleton mothers. Both mean lidocaine UV and UA levels were 35% higher in twin A (first-delivered) compared to the singleton neonate, (P < 0.01, t test). Similarly, twin B mean UV and UA lidocaine levels were 35% and 53% higher than the singleton value (P < 0.01). Mean UV and UA lidocaine fetal/maternal ratios in both twins were at least 18% higher than the singleton value (P < 0.05).'] Are plasma lidocaine concentrations higher in twin compared to singleton newborns following epidural anesthesia for Cesarean delivery?