No evidence of teratogenicity was found in mice, rats, or rabbits when
lamotrigine was orally administered
to pregnant animals during the period of organogenesis at doses up
to 1.2, 0.5, and 1.1 times, respectively, on a mg/m2 basis, the highest usual human maintenance dose (i.e., 500 mg/day). However, maternal toxicity and secondary fetal toxicity producing reduced fetal weight and/or delayed ossification were seen in mice and rats, but not in rabbits at these doses.