Concentrations of lamotrigine in a mother on lamotrigine treatment and her newborn child

Objective: To investigate the transfer of lamotrigine in pregnancy and during lactation from a mother on lamotrigine treatment to her child. Methods: Concentrations of lamotrigine were measured by high-pressure liquid chromatography in umbilical cord serum and in serum samples of the mother and her child as well as in the mother's milk during the first five postpartum months. Results: In the child lamotrigine serum concentrations (up to 2.8 mu g ml(-1)) comparable to those usually achieved in active treatment with lamotrigine were found not only after birth, but also during lactation. A considerable amount of lamotrigine (2-5 mg per day) was excreted in breast milk. No adverse effects were seen in the child. Conclusion: The transfer of lamotrigine taking place during pregnancy and lactation should not be neglected. In this case the child should be thoroughly observed for potential adverse effects.