This study is investigating the neurodevelopmental effects of prenatal exposure to lamotrigine (LTG), sodium valproate (VPA), or carbamazepine (CBZ) monotherapies. The hypotheses to be tested include:

1. Exposure during pregnancy to CBZ, LTG, and VPA, each as monotherapy, is associated with developmental delay with or without signs of autism.
2. Exposure to each drug (CBZ, LTG, and VPA) as monotherapy is associated with an increased rate of occurrence of major malformations.
3. The child with major malformations is more likely to have developmental delay with or without signs of autism than the child who does not have major malformations.
4. The occurrence of adaptive behavior outcomes will show a dose-response relationship with the dose of medication taken by the mother in the first trimester.

The study population includes children 36-83 months of age who were exposed throughout gestation to one of the three drugs of interest, as treatment for maternal seizure disorder.

Inclusion Criteria:

• 36-83 months of age
• Prenatal exposure to LTG, VPA, or CBZ monotherapy
• AED was used by mother to suppress seizures
• Mother was enrolled in the North American AED Pregnancy Registry

Exclusion Criteria:

• Exposure during the first trimester to other known teratogens.
• Mother with mental health issues
• Refusal to release medical records to confirm eligibility.

Children 36-83 months of age, prenatally exposed to LTG, VPA, or CBZ monotherapies, recruited through mothers enrolled in the North American Antiepileptic Drug Pregnancy Registry.