Final answer:
Drug category X refers to drugs that are unsafe for use during pregnancy due to potential harm to the fetus or the mother.
Step-by-step explanation:
Drug category X refers to drugs that are deemed unsafe for use during pregnancy. This categorization is based on an acceptable risk assessment that indicates potential harm to the fetus or the mother.\
An example of a drug in category X is thalidomide, which was prescribed to pregnant women in the 1950s and 1960s and resulted in severe birth defects. These drugs should be avoided during pregnancy to minimize the risks.