FDA Pregnancy Drug Categories

FDA PREGNANCY  CATEGORIES

The FDA-assigned pregnancy categories as used in the Drug Formulary  are as follows:

Category A

Adequate and well-controlled studies have failed to demonstrate a risk

to the fetus in the first trimester of pregnancy (and there is no evidence

of risk in later trimesters).

Category B

Animal reproduction studies have failed to demonstrate a risk to the

fetus and there are no adequate and well-controlled studies in pregnant

women.

Category C

Animal reproduction studies have shown an adverse effect on the fetus

and there are no adequate and well-controlled studies in humans, but

potential benefits may warrant use of the drug in pregnant women

despite potential risks.

Category D

There is positive evidence of human fetal risk based on adverse

reaction data from investigational or marketing experience or studies

in humans, but potential benefits may warrant use of the drug in

pregnant women despite potential risks.

Category X

Studies in animals or humans have demonstrated fetal abnormalities

and/or there is positive evidence of human fetal risk based on adverse

reaction data from investigational or marketing experience, and the

risks involved in use of the drug in pregnant women clearly outweigh

potential benefits.


NR: Not Rated