Pregnancy Category A. Controlled studies show no risk in pregnancy.

Controlled studies in pregnant women have not shown an increased risk of fetal abnormalities when the drug is administered during pregnancy. The possibility of fetal harm appears remote when the drug is used during pregnancy.

Pregnancy Category B. No evidence of risk in pregnancy.

1. Controlled studies in animals have shown that the drug poses a risk to the fetus. However, studies in pregnant women have failed to show such a risk.

2. Controlled studies in animals do not show evidence of impaired fertility or harm to the fetus. However, similar studies have not been performed in humans. Because animal studies are not entirely predictive of human response, the drug should be used during pregnancy only if clearly needed.

Pregnancy Category C. Risk in pregnancy cannot be ruled out.

Controlled studies either have not been conducted in animals or show that the drug is teratogenic or has an embryocidal effect and/or other adverse effect in animals. However, there are no adequate and well-controlled studies in pregnant women. The drug should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. The drug can cause fetal harm when administered to a pregnant woman. If the drug is used during pregnancy, or if a patient becomes pregnant while taking this drug, the patient should be informed of the potential hazard to the fetus. However, the potential benefits of treatment may outweigh any potential risk.

Pregnancy Category D. Clear evidence of risk in pregnancy.

The drug can cause fetal harm when administered to a pregnant woman. If the drug is used during pregnancy, or if a patient becomes pregnant while taking this drug, the patient should be informed of the potential hazard to the fetus. However, the potential benefits of treatment may outweigh any potential risk.

Pregnancy Category X. Absolutely contraindicated in pregnancy.

The drug has been shown to cause fetal harm when administered to a pregnant woman. The drug is absolutely contraindicated in women who are or who may become pregnant. If this drug is used during pregnancy or if a patient becomes pregnant while taking this drug, the patient should be informed of the potential hazard to the fetus. In this setting, the potential risk outweighs any potential benefit from treatment.