Which Statement Best Describes Our Current Understanding of This Issue

Which statement best describes our current understanding of this issue of drug ingestion during pregnancy?

A) As long as prescription drugs are taken in very low doses, no harmful effects will occur.
B) As long as the only drugs used are prescription drugs, there will be no adverse effects to the fetus.
C) Any over-the-counter drugs are safe for pregnant women and their developing fetuses.
D) Even if a drug is prescribed or sold over the counter, it may not be safe to use during pregnancy.