Final answer:
The pregnancy safety category for a medication that poses a significant risk to the fetus is Category X. Category X medications are considered contraindicated during pregnancy as they have been shown to cause fetal abnormalities and can pose serious risks to the developing fetus.
Step-by-step explanation:
The pregnancy safety category for a medication that poses a significant risk to the fetus is Category X. Category X medications are considered contraindicated during pregnancy as they have been shown to cause fetal abnormalities and can pose serious risks to the developing fetus. Examples of Category X medications include thalidomide, which caused limb defects in babies born to women who took this drug in the 1960s, and certain drugs like heroin, cocaine, and methamphetamine.