Lamotrigine in pregnancy and absent major malformations

Cunningham MC et al.  Final results from 18 years of the Lamotrigine Pregnancy Registry.  Neurology 2011; 76: 1817-1823. 

1558 first trimester exposures occurred.  There were 35 infants (2.2 %) with major congenital malformations.  This is similar to population based cohorts.  However, the number was 10.7%ammmong the 150 exposed both to lamotrigine and valproate in the first trimester and 2.8 % in 430 patients exposed to lamotrigine polytherapy without valproate.  Among patients with first trimester monopharmacy with lamotrigine, there were 3 cases of anencephaly, all of which were electively terminated.