It should be remembered that most drugs used in pregnancy, including steroids for the prevention of respiratory distress syndrome, all tocolytic agents, and magnesium sulfate for the prevention of cerebral palsy, to mention a few, have not been approved by the FDA. Yet, they are standard of care. In contrast, in the case of ondansetron there are unresolved issues surrounding the fetal and maternal safety, including recent warnings by the FDA on its potential to cause serious dysrhythmias