FDA Pregnancy Categories

No risk to fetus per studies

No risk in animal studies, and well-controlled studies in pregnant women not available. Assumed there is little or no risk.

Animal studies a risk to the fetus. Controlled studies on pregnant women not available. Risk vs. benefit of drug must be determined.

A risk to the human fetus has been proved. Risk vs. benefit must be determined.

A risk to the human fetus has been proved. Risk outweighs the benefit, and drug should be avoided during pregnancy.