In the May 24, 2011, issue of the journal Neurology, investigators from the International Lamotrigine Pregnancy Registry, which is sponsored by the manufacturer of Lamictal, GlaxoSmithKline, provided results of an 18 year research project observing the rate of congenital malformations that occur in relationship to exposure to first trimester lamotrigine therapy. Of 1,558 first trimester exposures to lamotrigine, 35 infants with major congenital malformations were observed. This represented 2.2% of this population and is similar to estimates from other general population-based groups. The observed proportion of infants with congenital malformation among 150 lamotrigine and valproic acid combination therapy was found to be 10.7% among 430 infants exposed to lamotrigine combination therapy. There was no consistent type of malformation that occurred. The investigators conclude that they did not detect an appreciable increase in malformation frequency after the use of first trimester lamotrigine. The proportion of infants with malformations who take lamotrigine in combination with valproic acid was high but is similar to what has been reported with valproic acid alone. Ongoing research will be needed to completely assure individuals who take this medication in their first trimester with regards to appropriate risk.

This study is important because it gives a sense of what happens over a long-term follow-through of women who have taken lamotrigine during their first trimester. It is reassuring to note that lamotrigine is relatively safe compared to other agents; however, lamotrigine in combination with valproic acid appears to be problematic as is valproic acid by itself as the sole medication for women. Moreover, the study continues to point out that valproic acid should likely be avoided in women who are of childbearing years or who plan to become pregnant.

Joseph Sirven, M.D.
Editor-in-Chief, epilepsy.com 
Last Reviewed: 6/15/11

Article from the June 2011 Epilepsy.com Spotlight Newsletter. Other articles in this issue inclue:

• On My Mind: The Lowdown on Phenytoin
• SUDEP Recommendations