Rubinchik-Stern M, et al. - This study characterized the effects of short exposure to valproic acid (VPA) on the expression of carriers for compounds essential for fetal development in human placentas ex vivo, under controlled conditions. VPA was found to considerably alter the mRNA levels of major carriers for folic acid, glucose, choline, thyroid hormones, and serotonin and reduced placental folate concentrations by 25%-35%. The placenta served as a novel target of VPA, which exhibited the potential involvement of the placenta in VPA's adverse fetal outcomes.