Safety During Pregnancy and Teratogenic Risk

Category A

Adequate studies in pregnant women have not demonstrated a risk to the fetus in the first trimester of pregnancy, and there is no evidence of risk in later trimesters.

Category B

Animal studies have not demonstrated a risk to the fetus, but there are no adequate studies in pregnant women, or animal studies have shown an adverse effect, but adequate studies in pregnant women have not demonstrated a risk to the fetus during the first trimester of pregnancy, and there is no evidence of risk in later trimesters.

Category C

Animal studies have shown an adverse effect on the fetus, but there are no adequate studies in humans; the benefits from the use of the drug in pregnant women may be acceptable despite its potential risks, or there are no animal reproduction studies and no adequate studies in humans.

Category D

There is evidence of human fetal risk, but the potential benefits from the use of the drug in pregnant women may be acceptable despite its potential risks

Category X

Studies in animals or humans demonstrate fetal abnormalities or adverse reactions; reports indicate evidence of fetal risk. The risk of use in a pregnant woman clearly outweighs any possible benefit.