Changing Australian prescribing patterns for antiepileptic drugs in pregnancy and their possible consequences.

We report progress in the accumulation of data by the Australian Pregnancy Register over 64 months, confirming the rise in enrollment and the predominantly epileptic indication for taking antiepileptic drugs. Eighty percent of the enrollment was prospective. The focus of the current report is the observation that as a possible result of education and dissemination of information about the risks of exposure to high-dose valproate, there has been a decline in the drug's doses prescribed in Australia, as well as a decline in the proportion of patients prescribed this drug in pregnancy. The risk of teratogenicity associated with valproate in doses in excess of 1100 mg/day was confirmed, and the incidence of lamotrigine-related malformations was comparable to that associated with exposure to phenytoin and carbamazepine. Reporting of data for this paper took into account the 12 months follow-up period for each pregnancy outcome, thus in effect making the evaluation period 21 months for each pregnancy and its outcome.