This index is based on the United States Food and Drug Administration (US FDA). The following categories do not imply an increasing progression of risk from A to X pregnancy categories. Drugs are categorized based on the risk of reproductive and developmental adverse effects and on risk versus benefit considerations. Drugs in categories D, X, and in some cases C, may pose similar risk, but may be categorized differently on the basis of different risk versus benefit considerations.
Some products have no pregnancy category indicated as “No Data”.
CATEGORY A – If adequate and well-controlled studies in pregnant women have failed to demonstrate a risk to the fetus in the first trimester of pregnancy (and there is no evidence of a risk in later trimesters), and the possibility of fetal harm remains remote. However, the drug should be used during pregnancy only if clearly needed.---------------
CATEGORY B – If animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women or animal reproduction studies have shown an adverse effect (other than a decrease in fertility) that was not confirmed in controlled studies in women in the first trimester (and there is no evidence of a risk in later trimesters). However, the drug should be used during pregnancy only if clearly needed.
CATEGORY C – If animal reproduction studies have shown an adverse effect on the fetus (teratogenic or embryocidal or other), if there are no adequate and well-controlled studies in humans, and if the benefits from the use of the drug in pregnant women may be acceptable despite its potential risks. The drug should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
CATEGORY D – If there is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but the potential benefits from the use of the drug in pregnant women may be acceptable despite its potential risks (e.g., if the drug is needed in a life-threatening situation or for a serious disease for which safer drugs cannot be used or are ineffective). If the drug is used during pregnancy or if the patient becomes pregnant while taking the drug, the patient should be apprised of the potential hazard to the fetus.
CATEGORY X - If studies in animals or humans have demonstrated fetal abnormalities or if there is positive evidence of fetal risk based on adverse reaction reports from investigational or marketing experience, or both, and the risk of the use of the drug in a pregnant woman clearly outweighs any possible benefit. The drug is contraindicated in women who are or may become pregnant.