Salivary concentrations of antiepileptic drugs, oestradiol and progesterone throughout pregnancy in epileptic women.

Epileptic women may experience an increase in seizure frequency during pregnancy. To explore the relationship between seizures, simultaneous antiepileptic drug and sex hormone concentrations, 8 pregnant epileptic women collected saliva each week throughout their pregnancies and for up to 6 weeks after delivery. The ratio of the drug dose to the drug's body fluid concentration at steady state (dose:Css), as measured by high performance liquid chromatography (HPLC), increased throughout pregnancy and fell in the 3rd to 4th week postpartum. There was no correlation between the dose:Css ratio and the salivary oestradiol concentration, nor between the number of seizures and the antiepileptic drug or sex hormone concentrations, and there was only a weak positive correlation between the dose:Css ratio and the salivary progesterone concentration. The possible interactions between sex hormone concentrations, antiepileptic drug concentrations and seizures are complex, and warrant further study in a greater number of pregnant subjects.