Do Anti-Epileptic Drug modifications after first trimester of pregnancy influence fetal malformation or cognitive outcome?

Objective: The management of Women With Epilepsy (WWE) in pregnancy is a challenge that demands balancing the risks of Major Congenital Malformation (MCM) on one hand with adequate seizure control on the other. While most studies have analysed the risks of Anti-Epileptic Drugs (AED) exposure in the first trimester, AED changes during the second and third trimester and their effects on fetal outcome has not been studied adequately. Materials and Methods: Data of WWE who were prospectively followed up and completed pregnancy with live birth under the Kerala registry of epilepsy and pregnancy (KREP) between 1998 and 2014 were analysed. The AED addition, dose escalation, unchanged continuation, dose reduction or stoppage during the second or third trimester in comparison to the first trimester was tabulated for each drug. The outcome measures evaluated were malformation status and Developmental Quotient (DQ) at one year as extracted from the clinical records of the registry. Results: The first trimester AED exposure was nil for 231, monotherapy for 925 and polytherapy for 391 WWE. WWE on monotherapy in first trimester were more likely to remain on the same number of AEDs in second or third trimester than those who were on polytherapy (OR 3.1, 95% CI 2.2 - 4.46). AED naive women had a higher likelihood (OR 16.7; 95% CI 10.9-25.8) of being started on AED than women on monotherapy being switched to polytherapy. At least one AED was reduced or stopped during second or third trimester more often in women on polytherapy (15.1%) than in women on monotherapy (3.7%) (OR 4.7; 95% CI 2.9-7.2). Malformation rates for the infants of women whose AED dosage was increased or added were not significantly different from those of others. There was no statistically significant change in DQ with increase in dose or addition of drugs in the second or third trimester. Conclusion: AEDs were reduced in a significant proportion of patients on polytherapy while more than a third of women who were not on AEDs in the first trimester were subsequently started on AEDs. Increase in dose or addition of AEDs after the first trimester is unlikely to influence malformation outcome but the potential adverse effect on the DQ needs to be explored on a larger set of data.