When pregnant, what is the most harmful drug according to the material?

• A. Cannabis
• B. Cocaine
• C. Heroin
• D. Alcohol

Answer: (D)

Alcohol is singled out because its harmful effects on a developing fetus are well-established and can occur even with what might be considered modest drinking. Alcohol crosses the placenta easily, and the fetus has a limited ability to metabolize it, so fetal blood alcohol levels can remain high for longer periods. This exposure can cause a range of serious problems known as fetal alcohol spectrum disorders, including distinctive facial features, growth deficiencies, and lifelong neurodevelopmental and cognitive problems. Importantly, there is no proven safe amount of alcohol in pregnancy, and the risk increases with the level and duration of exposure.

Other substances, like cannabis, cocaine, and heroin, carry significant risks as well—such as growth restriction, preterm birth, or withdrawal effects in the newborn—but they do not have the same established, dose-independent teratogenic potential as alcohol. That combination of widespread, lifelong impact and the lack of a safe threshold makes alcohol the most harmful option during pregnancy according to the material.