Teratogenesis is defined as what?

• A. The induction of defects in the fetus when a drug is given to a pregnant woman
• B. The transformation of a normal cell into a cancer cell
• C. An immune-mediated drug reaction
• D. The regression of a tumor

Answer: (A)

Teratogenesis refers to the process by which exposure to a substance during pregnancy causes defects in the developing fetus. This can include congenital malformations and other developmental abnormalities that arise when a drug or chemical disrupts normal embryonic or fetal development, often during organ formation when the fetus is most vulnerable. That’s why the statement describing induction of fetal defects due to a drug given to a pregnant woman is the correct description. The other options describe different drug-related effects: transforming normal cells into cancer cells is carcinogenesis, an immune-mediated drug reaction is hypersensitivity, and regression of a tumor is a therapeutic tumor response. For context, teratogens can cause a range of outcomes depending on dose and timing, with classic examples like certain drugs causing limb or organ defects if exposure occurs during critical windows.