What does FDA pregnancy category X indicate about a medication?

FDA pregnancy category X indicates that a medication has been demonstrated through human or animal studies to cause fetal abnormalities. In these cases, the risks of using the medication during pregnancy greatly outweigh any potential benefits. This categorization means that numerous studies have provided sufficient evidence showing that the drug can harm the developing fetus.

Medications classified as category X typically include those that have been associated with significant teratogenic effects, meaning they can cause developmental malformations in the fetus. Healthcare providers typically advise against the use of these medications in pregnant individuals due to the potential for serious risks to the fetus's health and development. Consequently, this category serves as a warning to avoid the medication altogether when pregnancy is a possibility.