Variations in the plasma concentration of levetiracetam during pregnancy and postpartum were prospectively monitored in five women to investigate their potential implications in epilepsy management and child outcome. Under unchanged levetiracetam dosages, the mean concentrations of levetiracetam during the third trimester were 62% of the baseline late (12 month) postpartum levels, but only 47% of the baseline early postpartum (2 month) levetiracetam levels. In dual therapy with lamotrigine, baseline late postpartum levetiracetam clearance was 63.2%, whereas in early postpartum it was 45% of the maximal second-trimester clearance. However, the number of seizures remained unchanged once lamotrigine dose was increased. No woman had adverse effects during the puerperium. The mean umbilical cord/maternal plasma concentration ratio was 1.21. None of the newborns had malformations, with the anthropometric data being normal for their gestational age. The decline in gestational levetiracetam plasma concentration does not seem to be hazardous, but differs according to whether early or late postpartum levels are chosen as baseline levels.