Epilepsy affects over 500,000 women of reproductive age in the U.S., and occurs in 0.5% of pregnancies. It is associated with higher risks of cesarean delivery, preterm birth, congenital malformations, and maternal mortality. Pregnancy alters the pharmacokinetics of antiepileptic drugs (AEDs), increasing the volume of distribution and renal clearance, which can lower serum drug levels and raise seizure risk. The American Academy of Neurology (AAN) and the Society for Maternal-Fetal Medicine (SMFM) recommend therapeutic drug monitoring (TDM) to maintain serum AED levels at 65% of preconception baseline.
Proactive AED dose adjustments based on TDM have shown improved seizure control. However, AED polytherapy has been associated with adverse perinatal outcomes, such as higher cesarean rates and preterm births. While TDM might improve outcomes by monitoring drug levels, there are limitations. Serum drug concentrations vary widely between patients, and standard assays often measure total rather than free drug concentrations, leading to potential inaccuracies. Additionally, a lack of preconception baselines and inconsistent monitoring complicates the application of TDM, and there is limited evidence linking AED levels to teratogenicity or improved clinical outcomes.
In clinical practice, AED monitoring is often inconsistent, with unclear schedules and variability in lab assay quality. Management frequently involves dose adjustments based on lab results rather than individualized therapeutic targets. Multiple healthcare providers managing epilepsy during pregnancy can further complicate responsibility for AED care.
The effectiveness of routine AED monitoring in improving maternal and neonatal outcomes, independent of seizure control, remains uncertain. Existing studies largely rely on expert consensus. This study aims to evaluate whether regular AED monitoring reduces adverse obstetric outcomes without increasing seizure frequency, addressing a critical gap in the current evidence base.