Final answer:
FDA pregnancy category X means the drug should not be administered to pregnant women due to potential teratogenic effects and associated risks to the fetus.
Step-by-step explanation:
The Food and Drug Administration (FDA) pregnancy category X indicates that a drug has been associated with teratogenic effects and is contraindicated in pregnancy. This means that the risks involved in the use of the drug in pregnant women clearly outweigh potential benefits. Category X drugs should not be used in pregnant women because they can cause fetal abnormalities or there is evidence of fetal risk based on human experience, or both, and the risk of using the drug in pregnant women clearly outweighs any possible benefit.