Pregnancy Drug Category
Category A
- - Controlled studies show no risk.
- - Adequate and well controlled studies in pregnant women have failed to demonstrate a risk to fetus in any trimester of pregnancy.
Category B
- - No evidence of risk in humans
- - Adequate and well controlled studies in pregnant women have not shown increased risk of fetal abnormalities despite adverse findings in animal or in the absence of adequate human studies, animal studies show no fetal risk. The chance of fetal harm is remote, but remains a possibility.
Category C
- - Risk cannot be ruled out
- - Adequate and well controlled human studies are lacking, and animal studies have shown a risk to the fetus or are lacking as well. There is a chance of fetal harm if the drug is administered during pregnancy; but potential benefits may outweigh the potential risk.
Category D
- - Positive evidence of Risk
- - Studies in humans, or investigational or post-marketing reports, have demonstrated fetal risk.
- E.g., the drug may be acceptable if needed in a life threatening situation or serious disease for which safer drugs cannot be used or are ineffective.
Category X
- - Contraindicated in Pregnancy
- - Studies in animals or humans, or investigational or post-marketing reports, have demonstrated positive evidence of fetal abnormalities or risk which clearly outweighs any possible benefits of the patient.
