FDA Pregnancy Category
Definition
A classification system (Categories A, B, C, D, X) that was used to indicate the risk of drug use during pregnancy. In 2015, the FDA replaced this system with the Pregnancy and Lactation Labeling Rule (PLLR), which provides more detailed narrative descriptions of risk.
Example
Isotretinoin (Accutane) was Category X — absolutely contraindicated in pregnancy due to severe birth defects.