Is There a Risk of Lidocaine in Placental Transfer?

You can actually get higher concentrations of lidocaine in the fetus because it'll become quote-unquote trapped there. The other thing to think about is protein binding. Protein concentrations and affinity for drugs on both maternal and fetal sides of placenta can influence transfer of the drugs. Typically the fetus doesn't do much metabolizing until later on because the fetus has what I would consider to be a dumb liver. And so they're actually not that many drugs at category A because you need sound scientific evidence to show their category A.