While vitamins and minerals are important
to a pregnant woman and her developing
fetus, Dr. Lund questions the use
of commercial dietary supplements, herbal remedies, or high doses of vitamins and minerals. "The simple answer is that we don't know if these are perfectly safe or not, because they are not regulated. It's very difficult for me to tell you with any certainty that they're safe. For instance, mega-doses of vitamin A have been associated with birth defects.