Safety Assessment of Medications during Pregnancy and Breastfeeding Based on Quantitative and Toxicological Analyses

The potential risks to the fetus or infant should be evaluated before initiating pharmacotherapy during pregnancy and breastfeeding. However, safety information and experiences during pregnancy and breastfeeding are often lacking because these populations are generally excluded from clinical drug development studies. Perinatal mental health is important. Based on quantitative and toxicological analyses, we focused on medications used in psychiatry and neurology during the perinatal period. As the placenta serves as a temporary but crucial organ for ensuring successful pregnancy and appropriate fetal growth, we assessed the effects of antiepileptic drugs (AEDs) on placental functions such as transport mechanisms, nutrient transport, and trophoblast differentiation. Several AEDs have been suggested to be transported to the placenta via carrier-mediated pathways in a series of studies. Valproic acid, known to pose several risks to the fetus, affects the gene expression of nutrient transporters and trophoblast differentiation. Furthermore, we established several quantitative methods, such as those for antianxiety and hypnotic drugs, to evaluate the safety of pharmacotherapy during breastfeeding using liquid chromatography-tandem mass spectrometry. The validated methods were applied to clinical samples donated by lactating women. In a series of studies, the importance of choosing a suitable method for sample preparation for each biological matrix has been highlighted. The results obtained from the clinical samples suggest the possibility of differences in transfer properties among drugs categorized in the same class. Furthermore, this research emphasizes the critical need to assess breast milk transfer in human studies because species differences have been suggested in some cases.