Table 2.

Categories of risk for drugs during pregnancy [38]

Category	Description
A	These drugs are the safest. Well-designed studies in people show no risks to the fetus.
B	Studies in animals show no risk to the fetus, and no well-designed studies in people have been done.
	or
	Studies in animals show a risk to the fetus, but well-designed studies in people do not.
C	No adequate studies in animals or people have been done.
D	Evidence shows a risk to the human fetus, but benefits of the drug may outweigh risks in certain situations. For example, the mother may have a life-threatening disorder or a serious disorder that cannot be treated with safer drugs.
X	Risk to the fetus has been proved to outweigh any possible benefit.